Subject: [PATCH V5 00/16] The Runtime Verification (RV) interface

Over the last years, I've been exploring the possibility of
verifying the Linux kernel behavior using Runtime Verification.

Runtime Verification (RV) is a lightweight (yet rigorous) method that
complements classical exhaustive verification techniques (such as model
checking and theorem proving) with a more practical approach for complex
systems.

Instead of relying on a fine-grained model of a system (e.g., a
re-implementation a instruction level), RV works by analyzing the trace of the
system's actual execution, comparing it against a formal specification of
the system behavior.

The usage of deterministic automaton for RV is a well-established
approach. In the specific case of the Linux kernel, you can check how
to model complex behavior of the Linux kernel with this paper:

De Oliveira, Daniel Bristot; Cucinotta, Tommaso; De Oliveira, Romulo Silva.
*Efficient formal verification for the Linux kernel.* In: International
Conference on Software Engineering and Formal Methods. Springer, Cham, 2019.
p. 315-332.

And how efficient is this approach here:

De Oliveira, Daniel B.; De Oliveira, Romulo S.; Cucinotta, Tommaso. *A thread
synchronization model for the PREEMPT_RT Linux kernel.* Journal of Systems
Architecture, 2020, 107: 101729.

tlrd: it is possible to model complex behaviors in a modular way, with
an acceptable overhead (even for production systems). See this
presentation at 2019's ELCE: https://www.youtube.com/watch?v=BfTuEHafNgg

Here I am proposing a more practical approach for the usage of deterministic
automata for runtime verification, and it includes:

- An interface for controlling the verification;
- A tool and set of headers that enables the automatic code
generation of the RV monitor (Monitor Synthesis);
- Sample monitors to evaluate the interface;

Given that RV is a tracing consumer, the code is being placed inside the
tracing subsystem (Steven and I have been talking about it for a while).

Features to be added after this patchset:
- safe_wtd monitor (requires further discussion with watchdog maintainers)
- Export symbols for external modules
- dot2bpf
- Add a reactor that enables the visualization of the visited
states via KCOV (Marco Elver & Dmitry Vyukov)
- Add a CRC method to check from user-space if the values
exported by the monitor were not corrupted by any other
kernel task (Gabriele Paoloni)

Changes from v4:
- The watchdog monitor will be discussed on another thread (Daniel)
- s/safe/final/ in the tracepoint definition (Daniel)
- Improved error handling at __init functions (Daniel)
- Remove the hostname from example of commands in a shell (Bagas Sanjaya)
- Added documentation about automata representation in C/DOT/Formal
and this documentation is cited in a comment on all model.h
(Steven)
- Make wwnr a single patch (Daniel/Steven)
- Add the .dot file for each monitor (Daniel)
- Add a document for each monitor (Daniel)
- Add an order for documentation in the index.rst (Daniel)
- Add wip/wwnr/... long description (Steven/Randy)
- Add comments for helper functions (Steven)
- Improve checks in da_monitor.h (Tao Zhou)
- Change final states set to bool (Tao/Daniel)
- Adjust indentation on enabling monitor/reactor (Steven)
- Use strim on buffers from user-space (Steven)
- Remove ifdefs inside functions (Steven)
- Adjust depends on RV in Kconfig (Steven)
- Check empty enabled monitor list (Tao Zhou)
- Fixed Copyright (Steven)
- Adjusted structures' indentation (Steven)
- Fix rv/monitors/$monitor/enabled return value (Song Liu)
- Typos (Punit Agrawal/Randy)
- Improved python scripts w.r.t. consistency (Steve)
- Blamed myself for so many problems :-) (Daniel's mind)
Changes from v3:
- Rebased on 5.19
(rostedt's request were made on 1x1 meetings)
- Moved monitors to monitors/$name/ (Rostedt)
- Consolidate the tracepoints into a single include file in the default
directory (trace/events/rv.h) (Rostedt)
- The tracepoints now record the entire string to the buffer.
- Change the enable_monitors to disable monitors with ! (instead of -).
(Rostedt)
- Add a suffix to the state/events enums, to avoid conflict in the
vmlinux.h used by eBPF.
- The models are now placed in the $name.h (it used to store the
tracepoints, but they are now consolidated in a single file)
- dot2c and dot2k updated to the changes
- models re-generated with these new standards.
- user-space tools moved to an directory outside of tools/tracing as
other methods of verification/log sources are planned.
Changes from v2:
- Tons of checkpatch and kernel test robot
- Moved files to better places
- Adjusted watchdog tracepoints patch (Guenter Roeck)
- Added pretimeout watchdog events (Peter Enderborg)
- Used task struct to store per-task monitors (Peter Zijlstra)
- Changed the instrumentation to use internal definition of tracepoint
and check the callback signature (Steven Rostedt)
- Used printk_deferred() and removed the comment about deadlocks
(Shuah Khan/John Ogness)
- Some simplifications:
- Removed the safe watchdog nowayout for now (myself)
- Removed export symbols for now (myself)
Changes from V1:
- rebased to the latest kernel;
- code cleanup;
- the watchdog dev monitor;
- safety app;


Daniel Bristot de Oliveira (16):
rv: Add Runtime Verification (RV) interface
rv: Add runtime reactors interface
rv/include: Add helper functions for deterministic automata
rv/include: Add deterministic automata monitor definition via C macros
rv/include: Add instrumentation helper functions
Documentation/rv: Add a basic documentation
tools/rv: Add dot2c
Documentation/rv: Add deterministic automaton documentation
tools/rv: Add dot2k
Documentation/rv: Add deterministic automata monitor synthesis
documentation
Documentation/rv: Add deterministic automata instrumentation
documentation
rv/monitor: Add the wip monitor skeleton created by dot2k
rv/monitor: Add the wip monitor
rv/monitor: Add the wwnr monitor
rv/reactor: Add the printk reactor
rv/reactor: Add the panic reactor

Documentation/trace/index.rst | 1 +
.../trace/rv/da_monitor_instrumentation.rst | 169 ++++
.../trace/rv/da_monitor_synthesis.rst | 147 ++++
.../trace/rv/deterministic_automata.rst | 184 +++++
Documentation/trace/rv/index.rst | 14 +
Documentation/trace/rv/monitor_wip.rst | 55 ++
Documentation/trace/rv/monitor_wwnr.rst | 45 ++
.../trace/rv/runtime-verification.rst | 233 ++++++
include/linux/rv.h | 35 +
include/linux/sched.h | 11 +
include/rv/automata.h | 75 ++
include/rv/da_monitor.h | 524 +++++++++++++
include/rv/instrumentation.h | 29 +
include/rv/rv.h | 32 +
include/trace/events/rv.h | 142 ++++
kernel/fork.c | 14 +
kernel/trace/Kconfig | 2 +
kernel/trace/Makefile | 1 +
kernel/trace/rv/Kconfig | 81 ++
kernel/trace/rv/Makefile | 8 +
kernel/trace/rv/monitors/wip/wip.c | 91 +++
kernel/trace/rv/monitors/wip/wip.h | 46 ++
kernel/trace/rv/monitors/wwnr/wwnr.c | 90 +++
kernel/trace/rv/monitors/wwnr/wwnr.h | 46 ++
kernel/trace/rv/reactor_panic.c | 43 +
kernel/trace/rv/reactor_printk.c | 42 +
kernel/trace/rv/rv.c | 739 ++++++++++++++++++
kernel/trace/rv/rv.h | 65 ++
kernel/trace/rv/rv_reactors.c | 488 ++++++++++++
kernel/trace/trace.c | 2 +
kernel/trace/trace.h | 9 +
tools/verification/dot2/Makefile | 26 +
tools/verification/dot2/automata.py | 174 +++++
tools/verification/dot2/dot2c | 26 +
tools/verification/dot2/dot2c.py | 254 ++++++
tools/verification/dot2/dot2k | 47 ++
tools/verification/dot2/dot2k.py | 177 +++++
.../dot2/dot2k_templates/main_global.c | 94 +++
.../dot2/dot2k_templates/main_per_cpu.c | 94 +++
.../dot2/dot2k_templates/main_per_task.c | 94 +++
tools/verification/models/wip.dot | 16 +
tools/verification/models/wwnr.dot | 16 +
42 files changed, 4481 insertions(+)
create mode 100644 Documentation/trace/rv/da_monitor_instrumentation.rst
create mode 100644 Documentation/trace/rv/da_monitor_synthesis.rst
create mode 100644 Documentation/trace/rv/deterministic_automata.rst
create mode 100644 Documentation/trace/rv/index.rst
create mode 100644 Documentation/trace/rv/monitor_wip.rst
create mode 100644 Documentation/trace/rv/monitor_wwnr.rst
create mode 100644 Documentation/trace/rv/runtime-verification.rst
create mode 100644 include/linux/rv.h
create mode 100644 include/rv/automata.h
create mode 100644 include/rv/da_monitor.h
create mode 100644 include/rv/instrumentation.h
create mode 100644 include/rv/rv.h
create mode 100644 include/trace/events/rv.h
create mode 100644 kernel/trace/rv/Kconfig
create mode 100644 kernel/trace/rv/Makefile
create mode 100644 kernel/trace/rv/monitors/wip/wip.c
create mode 100644 kernel/trace/rv/monitors/wip/wip.h
create mode 100644 kernel/trace/rv/monitors/wwnr/wwnr.c
create mode 100644 kernel/trace/rv/monitors/wwnr/wwnr.h
create mode 100644 kernel/trace/rv/reactor_panic.c
create mode 100644 kernel/trace/rv/reactor_printk.c
create mode 100644 kernel/trace/rv/rv.c
create mode 100644 kernel/trace/rv/rv.h
create mode 100644 kernel/trace/rv/rv_reactors.c
create mode 100644 tools/verification/dot2/Makefile
create mode 100644 tools/verification/dot2/automata.py
create mode 100644 tools/verification/dot2/dot2c
create mode 100644 tools/verification/dot2/dot2c.py
create mode 100644 tools/verification/dot2/dot2k
create mode 100644 tools/verification/dot2/dot2k.py
create mode 100644 tools/verification/dot2/dot2k_templates/main_global.c
create mode 100644 tools/verification/dot2/dot2k_templates/main_per_cpu.c
create mode 100644 tools/verification/dot2/dot2k_templates/main_per_task.c
create mode 100644 tools/verification/models/wip.dot
create mode 100644 tools/verification/models/wwnr.dot

--
2.35.1


Subject: [PATCH V5 13/16] rv/monitor: Add the wip monitor

The wakeup in preemptive (wip) monitor verifies if the
wakeup events always take place with preemption disabled:

|
|
v
#==================#
H preemptive H <+
#==================# |
| |
| preempt_disable | preempt_enable
v |
sched_waking +------------------+ |
+--------------- | | |
| | non_preemptive | |
+--------------> | | -+
+------------------+

The wakeup event always takes place with preemption disabled because
of the scheduler synchronization. However, because the preempt_count
and its trace event are not atomic with regard to interrupts, some
inconsistencies might happen.

The documentation illustrates one of these cases.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
Documentation/trace/rv/index.rst | 1 +
Documentation/trace/rv/monitor_wip.rst | 55 ++++++++++++++++++++++++++
include/trace/events/rv.h | 10 +++++
kernel/trace/rv/Kconfig | 13 ++++++
kernel/trace/rv/Makefile | 1 +
kernel/trace/rv/monitors/wip/wip.c | 51 +++++++-----------------
tools/verification/models/wip.dot | 16 ++++++++
7 files changed, 111 insertions(+), 36 deletions(-)
create mode 100644 Documentation/trace/rv/monitor_wip.rst
create mode 100644 tools/verification/models/wip.dot

diff --git a/Documentation/trace/rv/index.rst b/Documentation/trace/rv/index.rst
index db2ae3f90b90..4cb71ed628b8 100644
--- a/Documentation/trace/rv/index.rst
+++ b/Documentation/trace/rv/index.rst
@@ -10,3 +10,4 @@ Runtime Verification
deterministic_automata.rst
da_monitor_synthesis.rst
da_monitor_instrumentation.rst
+ monitor_wip.rst
diff --git a/Documentation/trace/rv/monitor_wip.rst b/Documentation/trace/rv/monitor_wip.rst
new file mode 100644
index 000000000000..0ea2d9388945
--- /dev/null
+++ b/Documentation/trace/rv/monitor_wip.rst
@@ -0,0 +1,55 @@
+Monitor wip
+===========
+
+ - Name: wip - wakeup in preemptive
+ - Type: per-cpu deterministic automaton
+ - Author: Daniel Bristot de Oliveira <[email protected]>
+
+Description
+-----------
+
+The wakeup in preemptive (wip) monitor is a sample per-cpu monitor
+that verifies if the wakeup events always take place with
+preemption disabled::
+
+ |
+ |
+ v
+ #==================#
+ H preemptive H <+
+ #==================# |
+ | |
+ | preempt_disable | preempt_enable
+ v |
+ sched_waking +------------------+ |
+ +--------------- | | |
+ | | non_preemptive | |
+ +--------------> | | -+
+ +------------------+
+
+The wakeup event always takes place with preemption disabled because
+of the scheduler synchronization. However, because the preempt_count
+and its trace event are not atomic with regard to interrupts, some
+inconsistencies might happen. For example::
+
+ preempt_disable() {
+ __preempt_count_add(1)
+ -------> smp_apic_timer_interrupt() {
+ preempt_disable()
+ do not trace (preempt count >= 1)
+
+ wake up a thread
+
+ preempt_enable()
+ do not trace (preempt count >= 1)
+ }
+ <------
+ trace_preempt_disable();
+ }
+
+This problem was reported and discussed here:
+ https://lore.kernel.org/r/[email protected]/
+
+Specification
+-------------
+Grapviz Dot file in tools/verification/models/wip.dot
diff --git a/include/trace/events/rv.h b/include/trace/events/rv.h
index 480aac18f403..90fa36cea517 100644
--- a/include/trace/events/rv.h
+++ b/include/trace/events/rv.h
@@ -56,6 +56,16 @@ DECLARE_EVENT_CLASS(error_da_monitor,
__entry->event,
__entry->state)
);
+
+#ifdef CONFIG_RV_MON_WIP
+DEFINE_EVENT(event_da_monitor, event_wip,
+ TP_PROTO(char *state, char *event, char *next_state, bool final_state),
+ TP_ARGS(state, event, next_state, final_state));
+
+DEFINE_EVENT(error_da_monitor, error_wip,
+ TP_PROTO(char *state, char *event),
+ TP_ARGS(state, event));
+#endif /* CONFIG_RV_MON_WIP */
#endif /* CONFIG_DA_MON_EVENTS_IMPLICIT */

#ifdef CONFIG_DA_MON_EVENTS_ID
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 7ad6c93cda64..8755ad74ec22 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -28,6 +28,19 @@ menuconfig RV
For further information, see:
Documentation/trace/rv/runtime-verification.rst

+config RV_MON_WIP
+ depends on RV
+ depends on PREEMPT_TRACER
+ select DA_MON_EVENTS_IMPLICIT
+ bool "wip monitor"
+ help
+ Enable wip (wakeup in preemptive) sample monitor that illustrates
+ the usage of per-cpu monitors, and one limitation of the
+ preempt_disable/enable events.
+
+ For further information, see:
+ Documentation/trace/rv/monitor_wip.rst
+
config RV_REACTORS
bool "Runtime verification reactors"
default y
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index 8944274d9b41..b41109d2750a 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -2,3 +2,4 @@

obj-$(CONFIG_RV) += rv.o
obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
+obj-$(CONFIG_RV_MON_WIP) += monitors/wip/wip.o
diff --git a/kernel/trace/rv/monitors/wip/wip.c b/kernel/trace/rv/monitors/wip/wip.c
index 9ac5dc9618a3..cda13ac8f6c0 100644
--- a/kernel/trace/rv/monitors/wip/wip.c
+++ b/kernel/trace/rv/monitors/wip/wip.c
@@ -10,44 +10,26 @@

#define MODULE_NAME "wip"

-/*
- * XXX: include required tracepoint headers, e.g.,
- * #include <linux/trace/events/sched.h>
- */
#include <trace/events/rv.h>
+#include <trace/events/sched.h>
+#include <trace/events/preemptirq.h>

-/*
- * This is the self-generated part of the monitor. Generally, there is no need
- * to touch this section.
- */
#include "wip.h"

-/*
- * Declare the deterministic automata monitor.
- *
- * The rv monitor reference is needed for the monitor declaration.
- */
struct rv_monitor rv_wip;
DECLARE_DA_MON_PER_CPU(wip, unsigned char);

-/*
- * This is the instrumentation part of the monitor.
- *
- * This is the section where manual work is required. Here the kernel events
- * are translated into model's event.
- *
- */
-static void handle_preempt_disable(void *data, /* XXX: fill header */)
+static void handle_preempt_disable(void *data, unsigned long ip, unsigned long parent_ip)
{
da_handle_event_wip(preempt_disable_wip);
}

-static void handle_preempt_enable(void *data, /* XXX: fill header */)
+static void handle_preempt_enable(void *data, unsigned long ip, unsigned long parent_ip)
{
- da_handle_event_wip(preempt_enable_wip);
+ da_handle_init_event_wip(preempt_enable_wip);
}

-static void handle_sched_waking(void *data, /* XXX: fill header */)
+static void handle_sched_waking(void *data, struct task_struct *task)
{
da_handle_event_wip(sched_waking_wip);
}
@@ -60,9 +42,9 @@ static int start_wip(void)
if (retval)
return retval;

- rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_disable);
- rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_enable);
- rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_sched_waking);
+ rv_attach_trace_probe("wip", preempt_disable, handle_preempt_disable);
+ rv_attach_trace_probe("wip", preempt_enable, handle_preempt_enable);
+ rv_attach_trace_probe("wip", sched_waking, handle_sched_waking);

return 0;
}
@@ -71,19 +53,16 @@ static void stop_wip(void)
{
rv_wip.enabled = 0;

- rv_detach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_disable);
- rv_detach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_enable);
- rv_detach_trace_probe("wip", /* XXX: tracepoint */, handle_sched_waking);
+ rv_detach_trace_probe("wip", preempt_disable, handle_preempt_disable);
+ rv_detach_trace_probe("wip", preempt_enable, handle_preempt_enable);
+ rv_detach_trace_probe("wip", sched_waking, handle_sched_waking);

da_monitor_destroy_wip();
}

-/*
- * This is the monitor register section.
- */
struct rv_monitor rv_wip = {
.name = "wip",
- .description = "auto-generated wip",
+ .description = "wakeup in preemptive per-cpu testing monitor.",
.start = start_wip,
.stop = stop_wip,
.reset = da_monitor_reset_all_wip,
@@ -108,5 +87,5 @@ module_init(register_wip);
module_exit(unregister_wip);

MODULE_LICENSE("GPL");
-MODULE_AUTHOR("dot2k: auto-generated");
-MODULE_DESCRIPTION("wip");
+MODULE_AUTHOR("Daniel Bristot de Oliveira <[email protected]>");
+MODULE_DESCRIPTION("wip: wakeup in preemptive - per-cpu sample monitor.");
diff --git a/tools/verification/models/wip.dot b/tools/verification/models/wip.dot
new file mode 100644
index 000000000000..2a53a9700a89
--- /dev/null
+++ b/tools/verification/models/wip.dot
@@ -0,0 +1,16 @@
+digraph state_automaton {
+ {node [shape = circle] "non_preemptive"};
+ {node [shape = plaintext, style=invis, label=""] "__init_preemptive"};
+ {node [shape = doublecircle] "preemptive"};
+ {node [shape = circle] "preemptive"};
+ "__init_preemptive" -> "preemptive";
+ "non_preemptive" [label = "non_preemptive"];
+ "non_preemptive" -> "non_preemptive" [ label = "sched_waking" ];
+ "non_preemptive" -> "preemptive" [ label = "preempt_enable" ];
+ "preemptive" [label = "preemptive"];
+ "preemptive" -> "non_preemptive" [ label = "preempt_disable" ];
+ { rank = min ;
+ "__init_preemptive";
+ "preemptive";
+ }
+}
--
2.35.1

Subject: [PATCH V5 06/16] Documentation/rv: Add a basic documentation

Add the runtime-verification.rst document, explaining the basics of RV
and how to use the interface.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
Documentation/trace/index.rst | 1 +
Documentation/trace/rv/index.rst | 9 +
.../trace/rv/runtime-verification.rst | 233 ++++++++++++++++++
kernel/trace/rv/Kconfig | 3 +
kernel/trace/rv/rv.c | 3 +
5 files changed, 249 insertions(+)
create mode 100644 Documentation/trace/rv/index.rst
create mode 100644 Documentation/trace/rv/runtime-verification.rst

diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index f9b7bcb5a630..2d73e8697523 100644
--- a/Documentation/trace/index.rst
+++ b/Documentation/trace/index.rst
@@ -32,3 +32,4 @@ Linux Tracing Technologies
sys-t
coresight/index
user_events
+ rv/index
diff --git a/Documentation/trace/rv/index.rst b/Documentation/trace/rv/index.rst
new file mode 100644
index 000000000000..b54e49b1d0de
--- /dev/null
+++ b/Documentation/trace/rv/index.rst
@@ -0,0 +1,9 @@
+====================
+Runtime Verification
+====================
+
+.. toctree::
+ :maxdepth: 2
+ :glob:
+
+ runtime-verification.rst
diff --git a/Documentation/trace/rv/runtime-verification.rst b/Documentation/trace/rv/runtime-verification.rst
new file mode 100644
index 000000000000..894037aef48d
--- /dev/null
+++ b/Documentation/trace/rv/runtime-verification.rst
@@ -0,0 +1,233 @@
+====================
+Runtime Verification
+====================
+
+Runtime Verification (RV) is a lightweight (yet rigorous) method that
+complements classical exhaustive verification techniques (such as *model
+checking* and *theorem proving*) with a more practical approach for complex
+systems.
+
+
+Instead of relying on a fine-grained model of a system (e.g., a
+re-implementation a instruction level), RV works by analyzing the trace of the
+system's actual execution, comparing it against a formal specification of
+the system behavior.
+
+The main advantage is that RV can give precise information on the runtime
+behavior of the monitored system, without the pitfalls of developing models
+that require a re-implementation of the entire system in a modeling language.
+Moreover, given an efficient monitoring method, it is possible execute an
+*online* verification of a system, enabling the *reaction* for unexpected
+events, avoiding, for example, the propagation of a failure on safety-critical
+systems.
+
+Runtime Monitors and Reactors
+=============================
+
+A monitor is the central part of the runtime verification of a system. The
+monitor stands in between the formal specification of the desired (or
+undesired) behavior, and the trace of the actual system.
+
+In Linux terms, the runtime verification monitors are encapsulated inside the
+*RV monitor* abstraction. A *RV monitor* includes a reference model of the
+system, a set of instances of the monitor (per-cpu monitor, per-task monitor,
+and so on), and the helper functions that glue the monitor to the system via
+trace, as depicted bellow::
+
+ Linux +---- RV Monitor ----------------------------------+ Formal
+ Realm | | Realm
+ +-------------------+ +----------------+ +-----------------+
+ | Linux kernel | | Monitor | | Reference |
+ | Tracing | -> | Instance(s) | <- | Model |
+ | (instrumentation) | | (verification) | | (specification) |
+ +-------------------+ +----------------+ +-----------------+
+ | | |
+ | V |
+ | +----------+ |
+ | | Reaction | |
+ | +--+--+--+-+ |
+ | | | | |
+ | | | +-> trace output ? |
+ +------------------------|--|----------------------+
+ | +----> panic ?
+ +-------> <user-specified>
+
+In addition to the verification and monitoring of the system, a monitor can
+react to an unexpected event. The forms of reaction can vary from logging the
+event occurrence to the enforcement of the correct behavior to the extreme
+action of taking a system down to avoid the propagation of a failure.
+
+In Linux terms, a *reactor* is an reaction method available for *RV monitors*.
+By default, all monitors should provide a trace output of their actions,
+which is already a reaction. In addition, other reactions will be available
+so the user can enable them as needed.
+
+For further information about the principles of runtime verification and
+RV applied to Linux:
+
+ Bartocci, Ezio, et al. *Introduction to runtime verification.* In: Lectures on
+ Runtime Verification. Springer, Cham, 2018. p. 1-33.
+
+ Falcone, Ylies, et al. *A taxonomy for classifying runtime verification tools.*
+ In: International Conference on Runtime Verification. Springer, Cham, 2018. p.
+ 241-262.
+
+ De Oliveira, Daniel Bristot. *Automata-based formal analysis and
+ verification of the real-time Linux kernel.* Ph.D. Thesis, 2020.
+
+Online RV monitors
+==================
+
+Monitors can be classified as *offline* and *online* monitors. *Offline*
+monitor process the traces generated by a system after the events, generally by
+reading the trace execution from a permanent storage system. *Online* monitors
+process the trace during the execution of the system. Online monitors are said
+to be *synchronous* if the processing of an event is attached to the system
+execution, blocking the system during the event monitoring. On the other hand,
+an *asynchronous* monitor has its execution detached from the system. Each type
+of monitor has a set of advantages. For example, *offline* monitors can be
+executed on different machines but require operations to save the log to a
+file. In contrast, *synchronous online* method can react at the exact moment
+a violation occurs.
+
+Another important aspect regarding monitors is the overhead associated with the
+event analysis. If the system generates events at a frequency higher than the
+monitor's ability to process them in the same system, only the *offline*
+methods are viable. On the other hand, if the tracing of the events incurs
+on higher overhead than the simple handling of an event by a monitor, then a
+*synchronous online* monitors will incur on lower overhead.
+
+Indeed, the research presented in:
+
+ De Oliveira, Daniel Bristot; Cucinotta, Tommaso; De Oliveira, Romulo Silva.
+ *Efficient formal verification for the Linux kernel.* In: International
+ Conference on Software Engineering and Formal Methods. Springer, Cham, 2019.
+ p. 315-332.
+
+Shows that for Deterministic Automata models, the synchronous processing of
+events in-kernel causes lower overhead than saving the same events to the trace
+buffer, not even considering collecting the trace for user-space analysis.
+This motivated the development of an in-kernel interface for online monitors.
+
+For further information about modeling of Linux kernel behavior using automata,
+see:
+
+ De Oliveira, Daniel B.; De Oliveira, Romulo S.; Cucinotta, Tommaso. *A thread
+ synchronization model for the PREEMPT_RT Linux kernel.* Journal of Systems
+ Architecture, 2020, 107: 101729.
+
+The user interface
+==================
+
+The user interface resembles the tracing interface (on purpose). It is
+currently at "/sys/kernel/tracing/rv/".
+
+The following files/folders are currently available:
+
+**available_monitors**
+
+- Reading list the available monitors, one per line
+
+For example::
+
+ # cat available_monitors
+ wip
+ wwnr
+
+**available_reactors**
+
+- Reading shows the available reactors, one per line.
+
+For example::
+
+ # cat available_reactors
+ nop
+ panic
+ printk
+
+**enabled_monitors**:
+
+- Reading lists the enabled monitors, one per line
+- Writing to it enables a given monitor
+- Writing a monitor name with a '-' prefix disables it
+- Truncating the file disables all enabled monitors
+
+For example::
+
+ # cat enabled_monitors
+ # echo wip > enabled_monitors
+ # echo wwnr >> enabled_monitors
+ # cat enabled_monitors
+ wip
+ wwnr
+ # echo '!wip' >> enabled_monitors
+ # cat enabled_monitors
+ wwnr
+ # echo > enabled_monitors
+ # cat enabled_monitors
+ #
+
+Note that it is possible to enable more than one monitor concurrently.
+
+
+**monitoring_on**
+
+This is an on/off general switcher for monitoring. It resembles the
+"tracing_on" switcher in the trace interface.
+
+- Writing "0" stops the monitoring
+- Writing "1" continues the monitoring
+- Reading returns the current status of the monitoring
+
+Note that it does not disable enabled monitors but stop the per-entity
+monitors monitoring the events received from the system.
+
+**reacting_on**
+
+- Writing "0" prevents reactions for happening
+- Writing "1" enable reactions
+- Reading returns the current status of the monitoring
+
+**monitors/**
+
+Each monitor will have its own directory inside "monitors/". There the
+monitor-specific files will be presented. The "monitors/" directory resembles
+the "events" directory on tracefs.
+
+For example::
+
+ # cd monitors/wip/
+ # ls
+ desc enable
+ # cat desc
+ wakeup in preemptive per-cpu testing monitor.
+ # cat enable
+ 0
+
+**monitors/$MONITOR/desc**
+
+- Reading shows a description of the monitor *$MONITOR*
+
+**monitors/$MONITOR/enable**
+
+- Writing "0" disables the *$MONITOR*
+- Writing "1" enables the *$MONITOR*
+- Reading return the current status of the *$MONITOR*
+
+**monitors/$MONITOR/reactors**
+
+- List available reactors, with the select reaction for the given *MONITOR*
+ inside "[]". The default one is the nop (no operation) reactor.
+- Writing the name of a reactor enables it to the given MONITOR.
+
+For example::
+
+ # cat monitors/wip/reactors
+ [nop]
+ panic
+ printk
+ # echo panic > monitors/wip/reactors
+ # cat monitors/wip/reactors
+ nop
+ [panic]
+ printk
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 0123bdf7052a..7ad6c93cda64 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -25,6 +25,9 @@ menuconfig RV
actual execution, comparing it against a formal specification of
the system behavior.

+ For further information, see:
+ Documentation/trace/rv/runtime-verification.rst
+
config RV_REACTORS
bool "Runtime verification reactors"
default y
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
index 00f1ffc49a7b..b2f963a54e3d 100644
--- a/kernel/trace/rv/rv.c
+++ b/kernel/trace/rv/rv.c
@@ -133,6 +133,9 @@
* auto-generated wakeup in preemptive monitor.
* # cat enable
* 0
+ *
+ * For further information, see:
+ * Documentation/trace/rv/runtime-verification.rst
*/

#include <linux/kernel.h>
--
2.35.1

Subject: [PATCH V5 02/16] rv: Add runtime reactors interface

A runtime monitor can cause a reaction to the detection of an
exception on the model's execution. By default, the monitors have
tracing reactions, printing the monitor output via tracepoints.
But other reactions can be added (on-demand) via this interface.

The user interface resembles the kernel tracing interface and
presents these files:

"available_reactors"
- Reading shows the available reactors, one per line.

For example:
# cat available_reactors
nop
panic
printk

"reacting_on"
- It is an on/off general switch for reactors, disabling
all reactions.

"monitors/MONITOR/reactors"
- List available reactors, with the select reaction for the given
MONITOR inside []. The default one is the nop (no operation)
reactor.
- Writing the name of a reactor enables it to the given
MONITOR.

For example:
# cat monitors/wip/reactors
[nop]
panic
printk
# echo panic > monitors/wip/reactors
# cat monitors/wip/reactors
nop
[panic]
printk

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
include/linux/rv.h | 11 +
kernel/trace/rv/Kconfig | 11 +
kernel/trace/rv/Makefile | 1 +
kernel/trace/rv/rv.c | 9 +
kernel/trace/rv/rv.h | 29 ++
kernel/trace/rv/rv_reactors.c | 488 ++++++++++++++++++++++++++++++++++
6 files changed, 549 insertions(+)
create mode 100644 kernel/trace/rv/rv_reactors.c

diff --git a/include/linux/rv.h b/include/linux/rv.h
index 0f7a1f9413a8..88d28d207f3a 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -7,6 +7,12 @@
#ifndef _LINUX_RV_H
#define _LINUX_RV_H

+struct rv_reactor {
+ char *name;
+ char *description;
+ void (*react)(char *msg);
+};
+
struct rv_monitor {
const char *name;
const char *description;
@@ -14,9 +20,14 @@ struct rv_monitor {
int (*start)(void);
void (*stop)(void);
void (*reset)(void);
+ void (*react)(char *msg);
};

extern bool monitoring_on;
int rv_unregister_monitor(struct rv_monitor *monitor);
int rv_register_monitor(struct rv_monitor *monitor);
+
+extern bool reacting_on;
+int rv_unregister_reactor(struct rv_reactor *reactor);
+int rv_register_reactor(struct rv_reactor *reactor);
#endif /* _LINUX_RV_H */
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 6d127cdb00dd..3eb5d48ab4f6 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -10,3 +10,14 @@ menuconfig RV
theorem proving). RV works by analyzing the trace of the system's
actual execution, comparing it against a formal specification of
the system behavior.
+
+config RV_REACTORS
+ bool "Runtime verification reactors"
+ default y
+ depends on RV
+ help
+ Enables the online runtime verification reactors. A runtime
+ monitor can cause a reaction to the detection of an exception
+ on the model's execution. By default, the monitors have
+ tracing reactions, printing the monitor output via tracepoints,
+ but other reactions can be added (on-demand) via this interface.
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index fd995379df67..8944274d9b41 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0

obj-$(CONFIG_RV) += rv.o
+obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
index d9199d1873bb..d988e2b1b9d2 100644
--- a/kernel/trace/rv/rv.c
+++ b/kernel/trace/rv/rv.c
@@ -343,6 +343,10 @@ static int create_monitor_dir(struct rv_monitor_def *mdef)
goto out_remove_root;
}

+ retval = reactor_create_monitor_files(mdef);
+ if (retval)
+ goto out_remove_root;
+
return 0;

out_remove_root:
@@ -687,6 +691,7 @@ void reset_all_monitors(void)
int __init rv_init_interface(void)
{
struct dentry *tmp;
+ int retval;

rv_root.root_dir = rv_create_dir("rv", NULL);
if (!rv_root.root_dir)
@@ -711,6 +716,10 @@ int __init rv_init_interface(void)
if (!tmp)
goto out_err;

+ retval = init_rv_reactors(rv_root.root_dir);
+ if (retval)
+ goto out_err;
+
monitoring_on = true;

return 0;
diff --git a/kernel/trace/rv/rv.h b/kernel/trace/rv/rv.h
index 6b8eff6725d9..5dd2f56ff953 100644
--- a/kernel/trace/rv/rv.h
+++ b/kernel/trace/rv/rv.h
@@ -18,13 +18,27 @@ struct rv_interface {
#define rv_remove tracefs_remove

#define MAX_RV_MONITOR_NAME_SIZE 32
+#define MAX_RV_REACTOR_NAME_SIZE 32

extern struct mutex rv_interface_lock;

+#ifdef CONFIG_RV_REACTORS
+struct rv_reactor_def {
+ struct list_head list;
+ struct rv_reactor *reactor;
+ /* protected by the monitor interface lock */
+ int counter;
+};
+#endif
+
struct rv_monitor_def {
struct list_head list;
struct rv_monitor *monitor;
struct dentry *root_d;
+#ifdef CONFIG_RV_REACTORS
+ struct rv_reactor_def *rdef;
+ bool reacting;
+#endif
bool task_monitor;
};

@@ -34,3 +48,18 @@ void reset_all_monitors(void);
int init_rv_monitors(struct dentry *root_dir);
int get_task_monitor_slot(void);
void put_task_monitor_slot(int slot);
+
+#ifdef CONFIG_RV_REACTORS
+extern bool reacting_on;
+int reactor_create_monitor_files(struct rv_monitor_def *mdef);
+int init_rv_reactors(struct dentry *root_dir);
+#else
+static inline int reactor_create_monitor_files(struct rv_monitor_def *mdef)
+{
+ return 0;
+}
+static inline int init_rv_reactors(struct dentry *root_dir)
+{
+ return 0;
+}
+#endif
diff --git a/kernel/trace/rv/rv_reactors.c b/kernel/trace/rv/rv_reactors.c
new file mode 100644
index 000000000000..27f48fec5a51
--- /dev/null
+++ b/kernel/trace/rv/rv_reactors.c
@@ -0,0 +1,488 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+ *
+ * Runtime reactor interface.
+ *
+ * A runtime monitor can cause a reaction to the detection of an
+ * exception on the model's execution. By default, the monitors have
+ * tracing reactions, printing the monitor output via tracepoints.
+ * But other reactions can be added (on-demand) via this interface.
+ *
+ * == Registering reactors ==
+ *
+ * The struct rv_reactor defines a callback function to be executed
+ * in case of a model exception happens. The callback function
+ * receives a message to be (optionally) printed before executing
+ * the reaction.
+ *
+ * A RV reactor is registered via:
+ * int rv_register_reactor(struct rv_reactor *reactor)
+ * And unregistered via:
+ * int rv_unregister_reactor(struct rv_reactor *reactor)
+ *
+ * These functions are exported to modules, enabling reactors to be
+ * dynamically loaded.
+ *
+ * == User interface ==
+ *
+ * The user interface resembles the kernel tracing interface and
+ * presents these files:
+ *
+ * "available_reactors"
+ * - List the available reactors, one per line.
+ *
+ * For example:
+ * # cat available_reactors
+ * nop
+ * panic
+ * printk
+ *
+ * "reacting_on"
+ * - It is an on/off general switch for reactors, disabling
+ * all reactions.
+ *
+ * "monitors/MONITOR/reactors"
+ * - List available reactors, with the select reaction for the given
+ * MONITOR inside []. The default one is the nop (no operation)
+ * reactor.
+ * - Writing the name of an reactor enables it to the given
+ * MONITOR.
+ *
+ * For example:
+ * # cat monitors/wip/reactors
+ * [nop]
+ * panic
+ * printk
+ * # echo panic > monitors/wip/reactors
+ * # cat monitors/wip/reactors
+ * nop
+ * [panic]
+ * printk
+ */
+
+#include <linux/slab.h>
+
+#include "rv.h"
+
+bool __read_mostly reacting_on;
+
+/*
+ * Interface for the reactor register.
+ */
+LIST_HEAD(rv_reactors_list);
+
+static struct rv_reactor_def *get_reactor_rdef_by_name(char *name)
+{
+ struct rv_reactor_def *r;
+
+ list_for_each_entry(r, &rv_reactors_list, list) {
+ if (strcmp(name, r->reactor->name) == 0)
+ return r;
+ }
+ return NULL;
+}
+
+/*
+ * Available reactors seq functions.
+ */
+static int reactors_show(struct seq_file *m, void *p)
+{
+ struct rv_reactor_def *rea_def = p;
+
+ seq_printf(m, "%s\n", rea_def->reactor->name);
+ return 0;
+}
+
+static void reactors_stop(struct seq_file *m, void *p)
+{
+ mutex_unlock(&rv_interface_lock);
+}
+
+static void *reactors_start(struct seq_file *m, loff_t *pos)
+{
+ mutex_lock(&rv_interface_lock);
+ return seq_list_start(&rv_reactors_list, *pos);
+}
+
+static void *reactors_next(struct seq_file *m, void *p, loff_t *pos)
+{
+ return seq_list_next(p, &rv_reactors_list, pos);
+}
+
+/*
+ * available reactors seq definition.
+ */
+static const struct seq_operations available_reactors_seq_ops = {
+ .start = reactors_start,
+ .next = reactors_next,
+ .stop = reactors_stop,
+ .show = reactors_show
+};
+
+/*
+ * available_reactors interface.
+ */
+static int available_reactors_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &available_reactors_seq_ops);
+};
+
+static const struct file_operations available_reactors_ops = {
+ .open = available_reactors_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release
+};
+
+/*
+ * Monitor reactor file.
+ */
+static int monitor_reactor_show(struct seq_file *m, void *p)
+{
+ struct rv_monitor_def *mdef = m->private;
+ struct rv_reactor_def *rdef = p;
+
+ if (mdef->rdef == rdef)
+ seq_printf(m, "[%s]\n", rdef->reactor->name);
+ else
+ seq_printf(m, "%s\n", rdef->reactor->name);
+ return 0;
+}
+
+/*
+ * available reactors seq definition.
+ */
+static const struct seq_operations monitor_reactors_seq_ops = {
+ .start = reactors_start,
+ .next = reactors_next,
+ .stop = reactors_stop,
+ .show = monitor_reactor_show
+};
+
+static ssize_t
+monitor_reactors_write(struct file *file, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
+ struct rv_monitor_def *mdef;
+ struct rv_reactor_def *rdef;
+ struct seq_file *seq_f;
+ int retval = -EINVAL;
+ bool enabled;
+ char *ptr;
+ int len;
+
+ if (count < 1 || count > MAX_RV_REACTOR_NAME_SIZE + 2)
+ return -EINVAL;
+
+ memset(buff, 0, sizeof(buff));
+
+ retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf,
+ count);
+ if (!retval)
+ return -EFAULT;
+
+ ptr = strim(buff);
+
+ len = strlen(ptr);
+ if (!len)
+ return count;
+
+ /*
+ * See monitor_reactors_open()
+ */
+ seq_f = file->private_data;
+ mdef = seq_f->private;
+
+ mutex_lock(&rv_interface_lock);
+
+ retval = -EINVAL;
+
+ /*
+ * nop special case: disable reacting.
+ */
+ if (strcmp(ptr, "nop") == 0) {
+
+ enabled = mdef->monitor->enabled;
+ if (enabled)
+ mdef->monitor->stop();
+
+ mdef->rdef = get_reactor_rdef_by_name("nop");
+ mdef->reacting = false;
+ mdef->monitor->react = NULL;
+
+ if (enabled) {
+ mdef->monitor->start();
+ mdef->monitor->enabled = 1;
+ }
+
+ retval = count;
+ goto unlock;
+ }
+
+ list_for_each_entry(rdef, &rv_reactors_list, list) {
+ if (strcmp(ptr, rdef->reactor->name) != 0)
+ continue;
+
+ /*
+ * found!
+ */
+ enabled = mdef->monitor->enabled;
+ if (enabled)
+ mdef->monitor->stop();
+
+ mdef->rdef = rdef;
+ mdef->reacting = true;
+ mdef->monitor->react = rdef->reactor->react;
+
+ if (enabled) {
+ mdef->monitor->start();
+ mdef->monitor->enabled = 1;
+ }
+
+ retval = count;
+ break;
+ }
+
+unlock:
+ mutex_unlock(&rv_interface_lock);
+
+ return retval;
+}
+
+/*
+ * available_reactors interface.
+ */
+static int monitor_reactors_open(struct inode *inode, struct file *file)
+{
+ /*
+ * create file "private" info is stored in the inode->i_private
+ */
+ struct rv_monitor_def *mdef = inode->i_private;
+ struct seq_file *seq_f;
+ int ret;
+
+ ret = seq_open(file, &monitor_reactors_seq_ops);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * seq_open stores the seq_file on the file->private data.
+ */
+ seq_f = file->private_data;
+
+ /*
+ * Copy the create file "private" data to the seq_file
+ * private data.
+ */
+ seq_f->private = mdef;
+
+ return 0;
+};
+
+static const struct file_operations monitor_reactors_ops = {
+ .open = monitor_reactors_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+ .write = monitor_reactors_write
+};
+
+static int __rv_register_reactor(struct rv_reactor *reactor)
+{
+ struct rv_reactor_def *r;
+
+ list_for_each_entry(r, &rv_reactors_list, list) {
+ if (strcmp(reactor->name, r->reactor->name) == 0) {
+ pr_info("Reactor %s is already registered\n",
+ reactor->name);
+ return -EINVAL;
+ }
+ }
+
+ r = kzalloc(sizeof(struct rv_reactor_def), GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+
+ r->reactor = reactor;
+ r->counter = 0;
+
+ list_add_tail(&r->list, &rv_reactors_list);
+
+ return 0;
+}
+
+/**
+ * rv_register_reactor - register a rv reactor.
+ * @reactor: The rv_reactor to be registered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_register_reactor(struct rv_reactor *reactor)
+{
+ int retval = 0;
+
+ if (strlen(reactor->name) >= MAX_RV_REACTOR_NAME_SIZE) {
+ pr_info("Reactor %s has a name longer than %d\n",
+ reactor->name, MAX_RV_MONITOR_NAME_SIZE);
+ return -EINVAL;
+ }
+
+ mutex_lock(&rv_interface_lock);
+ retval = __rv_register_reactor(reactor);
+ mutex_unlock(&rv_interface_lock);
+ return retval;
+}
+
+/**
+ * rv_unregister_reactor - unregister a rv reactor.
+ * @reactor: The rv_reactor to be unregistered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_unregister_reactor(struct rv_reactor *reactor)
+{
+ struct rv_reactor_def *ptr, *next;
+
+ mutex_lock(&rv_interface_lock);
+
+ list_for_each_entry_safe(ptr, next, &rv_reactors_list, list) {
+ if (strcmp(reactor->name, ptr->reactor->name) == 0) {
+
+ if (!ptr->counter) {
+ list_del(&ptr->list);
+ } else {
+ printk(KERN_WARNING
+ "rv: the rv_reactor %s is in use by %d monitor(s)\n",
+ ptr->reactor->name, ptr->counter);
+ printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
+ ptr->reactor->name);
+ return -EBUSY;
+ }
+
+ }
+ }
+
+ mutex_unlock(&rv_interface_lock);
+ return 0;
+}
+
+/*
+ * reacting_on interface.
+ */
+static ssize_t reacting_on_read_data(struct file *filp,
+ char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char *buff;
+
+ mutex_lock(&rv_interface_lock);
+ buff = reacting_on ? "1\n" : "0\n";
+ mutex_unlock(&rv_interface_lock);
+
+ return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
+}
+
+static void turn_reacting_off(void)
+{
+ reacting_on = false;
+}
+
+static void turn_reacting_on(void)
+{
+ reacting_on = true;
+}
+
+static ssize_t
+reacting_on_write_data(struct file *filp, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ int retval;
+ bool val;
+
+ retval = kstrtobool_from_user(user_buf, count, &val);
+ if (retval)
+ return retval;
+
+ mutex_lock(&rv_interface_lock);
+
+ if (val)
+ turn_reacting_on();
+ else
+ turn_reacting_off();
+
+ mutex_unlock(&rv_interface_lock);
+
+ return count;
+}
+
+static const struct file_operations reacting_on_fops = {
+ .open = simple_open,
+ .llseek = no_llseek,
+ .write = reacting_on_write_data,
+ .read = reacting_on_read_data,
+};
+
+int reactor_create_monitor_files(struct rv_monitor_def *mdef)
+{
+ struct dentry *tmp;
+
+ tmp = rv_create_file("reactors", RV_MODE_WRITE, mdef->root_d, mdef, &monitor_reactors_ops);
+ if (!tmp)
+ return -ENOMEM;
+
+ /*
+ * Configure as the rv_nop reactor.
+ */
+ mdef->rdef = get_reactor_rdef_by_name("nop");
+ mdef->reacting = false;
+
+ return 0;
+}
+
+/*
+ * None reactor register
+ */
+static void rv_nop_reaction(char *msg)
+{
+}
+
+struct rv_reactor rv_nop = {
+ .name = "nop",
+ .description = "no-operation reactor: do nothing.",
+ .react = rv_nop_reaction
+};
+
+/*
+ * This section collects the rv/ root dir files and folders.
+ */
+int init_rv_reactors(struct dentry *root_dir)
+{
+ struct dentry *available, *reacting;
+ int retval;
+
+ available = rv_create_file("available_reactors", RV_MODE_READ, root_dir, NULL,
+ &available_reactors_ops);
+ if (!available)
+ goto out_err;
+
+ reacting = rv_create_file("reacting_on", RV_MODE_WRITE, root_dir, NULL, &reacting_on_fops);
+ if (!reacting)
+ goto rm_available;
+
+ retval = __rv_register_reactor(&rv_nop);
+ if (retval)
+ goto rm_reacting;
+
+ reacting_on = 1;
+
+ return 0;
+
+rm_reacting:
+ rv_remove(reacting);
+rm_available:
+ rv_remove(available);
+out_err:
+ return -ENOMEM;
+}
--
2.35.1

Subject: [PATCH V5 16/16] rv/reactor: Add the panic reactor

Sample reactor that panics the system when an exception is found. This
is useful both to capture a vmcore, or to fail-safe a critical system.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
kernel/trace/rv/Kconfig | 8 ++++++
kernel/trace/rv/Makefile | 1 +
kernel/trace/rv/reactor_panic.c | 43 +++++++++++++++++++++++++++++++++
3 files changed, 52 insertions(+)
create mode 100644 kernel/trace/rv/reactor_panic.c

diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index f1d92d431130..ce2a90a89f55 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -71,3 +71,11 @@ config RV_REACT_PRINTK
help
Enables the printk reactor. The printk reactor emits a printk()
message if an exception is found.
+
+config RV_REACT_PANIC
+ bool "Panic reactor"
+ depends on RV_REACTORS
+ default y
+ help
+ Enables the panic reactor. The panic reactor emits a printk()
+ message if an exception is found and panic()s the system.
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index a13c750a35c1..963d14875b45 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_RV_MON_WIP) += monitors/wip/wip.o
obj-$(CONFIG_RV_MON_WWNR) += monitors/wwnr/wwnr.o
obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
+obj-$(CONFIG_RV_REACT_PANIC) += reactor_panic.o
diff --git a/kernel/trace/rv/reactor_panic.c b/kernel/trace/rv/reactor_panic.c
new file mode 100644
index 000000000000..c9b9ed99495b
--- /dev/null
+++ b/kernel/trace/rv/reactor_panic.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+ *
+ * Panic RV reactor:
+ * Prints the exception msg to the kernel message log and panic().
+ */
+
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+
+static void rv_panic_reaction(char *msg)
+{
+ panic(msg);
+}
+
+struct rv_reactor rv_panic = {
+ .name = "panic",
+ .description = "panic the system if an exception is found.",
+ .react = rv_panic_reaction
+};
+
+int register_react_panic(void)
+{
+ rv_register_reactor(&rv_panic);
+ return 0;
+}
+
+void unregister_react_panic(void)
+{
+ rv_unregister_reactor(&rv_panic);
+}
+
+module_init(register_react_panic);
+module_exit(unregister_react_panic);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira");
+MODULE_DESCRIPTION("panic rv reactor: panic if an exception is found");
--
2.35.1

Subject: [PATCH V5 14/16] rv/monitor: Add the wwnr monitor

Per task wakeup while not running (wwnr) monitor.

This model is broken, the reason is that a task can be running in the
processor without being set as RUNNABLE. Think about a task about to
sleep:

1: set_current_state(TASK_UNINTERRUPTIBLE);
2: schedule();

And then imagine an IRQ happening in between the lines one and two,
waking the task up. BOOM, the wakeup will happen while the task is
running.

Q: Why do we need this model, so?
A: To test the reactors.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
Documentation/trace/rv/index.rst | 1 +
Documentation/trace/rv/monitor_wwnr.rst | 45 +++++++++++++
include/trace/events/rv.h | 12 ++++
kernel/trace/rv/Kconfig | 12 ++++
kernel/trace/rv/Makefile | 1 +
kernel/trace/rv/monitors/wwnr/wwnr.c | 90 +++++++++++++++++++++++++
kernel/trace/rv/monitors/wwnr/wwnr.h | 46 +++++++++++++
tools/verification/models/wwnr.dot | 16 +++++
8 files changed, 223 insertions(+)
create mode 100644 Documentation/trace/rv/monitor_wwnr.rst
create mode 100644 kernel/trace/rv/monitors/wwnr/wwnr.c
create mode 100644 kernel/trace/rv/monitors/wwnr/wwnr.h
create mode 100644 tools/verification/models/wwnr.dot

diff --git a/Documentation/trace/rv/index.rst b/Documentation/trace/rv/index.rst
index 4cb71ed628b8..15fa966102c0 100644
--- a/Documentation/trace/rv/index.rst
+++ b/Documentation/trace/rv/index.rst
@@ -11,3 +11,4 @@ Runtime Verification
da_monitor_synthesis.rst
da_monitor_instrumentation.rst
monitor_wip.rst
+ monitor_wwnr.rst
diff --git a/Documentation/trace/rv/monitor_wwnr.rst b/Documentation/trace/rv/monitor_wwnr.rst
new file mode 100644
index 000000000000..cfa6abe867e6
--- /dev/null
+++ b/Documentation/trace/rv/monitor_wwnr.rst
@@ -0,0 +1,45 @@
+Monitor wwnr
+============
+
+ - Name: wwrn - wakeup while not running
+ - Type: per-task deterministic automaton
+ - Author: Daniel Bristot de Oliveira <[email protected]>
+
+Description
+-----------
+
+This is a per-task sample monitor, with the following
+definition::
+
+ |
+ |
+ v
+ wakeup +-------------+
+ +--------- | |
+ | | not_running |
+ +--------> | | <+
+ +-------------+ |
+ | |
+ | switch_in | switch_out
+ v |
+ +-------------+ |
+ | running | -+
+ +-------------+
+
+This model is borken, the reason is that a task can be running
+in the processor without being set as RUNNABLE. Think about a
+task about to sleep::
+
+ 1: set_current_state(TASK_UNINTERRUPTIBLE);
+ 2: schedule();
+
+And then imagine an IRQ happening in between the lines one and two,
+waking the task up. BOOM, the wakeup will happen while the task is
+running.
+
+- Why do we need this model, so?
+- To test the reactors.
+
+Specification
+-------------
+Grapviz Dot file in tools/verification/models/wwnr.dot
diff --git a/include/trace/events/rv.h b/include/trace/events/rv.h
index 90fa36cea517..495d3eece0ee 100644
--- a/include/trace/events/rv.h
+++ b/include/trace/events/rv.h
@@ -122,6 +122,18 @@ DECLARE_EVENT_CLASS(error_da_monitor_id,
__entry->event,
__entry->state)
);
+
+#ifdef CONFIG_RV_MON_WWNR
+/* id is the pid of the task */
+DEFINE_EVENT(event_da_monitor_id, event_wwnr,
+ TP_PROTO(int id, char *state, char *event, char *next_state, bool final_state),
+ TP_ARGS(id, state, event, next_state, final_state));
+
+DEFINE_EVENT(error_da_monitor_id, error_wwnr,
+ TP_PROTO(int id, char *state, char *event),
+ TP_ARGS(id, state, event));
+#endif /* CONFIG_RV_MON_WWNR */
+
#endif /* CONFIG_DA_MON_EVENTS_ID */
#endif /* _TRACE_RV_H */

diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 8755ad74ec22..d8c40fd67e88 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -41,6 +41,18 @@ config RV_MON_WIP
For further information, see:
Documentation/trace/rv/monitor_wip.rst

+config RV_MON_WWNR
+ depends on RV
+ select DA_MON_EVENTS_ID
+ bool "wwnr monitor"
+ help
+ Enable wwnr (wakeup while not running) sample monitor, this is a
+ sample monitor that illustrates the usage of per-task monitor.
+ The model is borken on purpose: it serves to test reactors.
+
+ For further information, see:
+ Documentation/trace/rv/monitor_wwnr.rst
+
config RV_REACTORS
bool "Runtime verification reactors"
default y
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index b41109d2750a..af0ff9a46418 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -3,3 +3,4 @@
obj-$(CONFIG_RV) += rv.o
obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
obj-$(CONFIG_RV_MON_WIP) += monitors/wip/wip.o
+obj-$(CONFIG_RV_MON_WWNR) += monitors/wwnr/wwnr.o
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.c b/kernel/trace/rv/monitors/wwnr/wwnr.c
new file mode 100644
index 000000000000..77b4692b3a5a
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+#include <rv/instrumentation.h>
+#include <rv/da_monitor.h>
+
+#define MODULE_NAME "wwnr"
+
+#include <trace/events/rv.h>
+#include <trace/events/sched.h>
+
+#include "wwnr.h"
+
+struct rv_monitor rv_wwnr;
+DECLARE_DA_MON_PER_TASK(wwnr, unsigned char);
+
+static void handle_switch(void *data, bool preempt, struct task_struct *p,
+ struct task_struct *n, unsigned int prev_state)
+{
+ /* start monitoring only after the first suspension */
+ if (prev_state == TASK_INTERRUPTIBLE)
+ da_handle_init_event_wwnr(p, switch_out_wwnr);
+ else
+ da_handle_event_wwnr(p, switch_out_wwnr);
+
+ da_handle_event_wwnr(n, switch_in_wwnr);
+}
+
+static void handle_wakeup(void *data, struct task_struct *p)
+{
+ da_handle_event_wwnr(p, wakeup_wwnr);
+}
+
+static int start_wwnr(void)
+{
+ int retval;
+
+ retval = da_monitor_init_wwnr();
+ if (retval)
+ return retval;
+
+ rv_attach_trace_probe("wwnr", sched_switch, handle_switch);
+ rv_attach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
+
+ return 0;
+}
+
+static void stop_wwnr(void)
+{
+ rv_wwnr.enabled = 0;
+
+ rv_detach_trace_probe("wwnr", sched_switch, handle_switch);
+ rv_detach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
+
+ da_monitor_destroy_wwnr();
+}
+
+struct rv_monitor rv_wwnr = {
+ .name = "wwnr",
+ .description = "wakeup while not running per-task testing model.",
+ .start = start_wwnr,
+ .stop = stop_wwnr,
+ .reset = da_monitor_reset_all_wwnr,
+ .enabled = 0,
+};
+
+static int register_wwnr(void)
+{
+ rv_register_monitor(&rv_wwnr);
+ return 0;
+}
+
+static void unregister_wwnr(void)
+{
+ if (rv_wwnr.enabled)
+ stop_wwnr();
+
+ rv_unregister_monitor(&rv_wwnr);
+}
+
+module_init(register_wwnr);
+module_exit(unregister_wwnr);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira <[email protected]>");
+MODULE_DESCRIPTION("wwnr: wakeup while not running monitor");
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.h b/kernel/trace/rv/monitors/wwnr/wwnr.h
new file mode 100644
index 000000000000..d1afe55cdd4c
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.h
@@ -0,0 +1,46 @@
+/*
+ * Automatically generated C representation of wwnr automaton
+ * For further information about this format, see kernel documentation:
+ * Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_wwnr {
+ not_running_wwnr = 0,
+ running_wwnr,
+ state_max_wwnr
+};
+
+#define INVALID_STATE state_max_wwnr
+
+enum events_wwnr {
+ switch_in_wwnr = 0,
+ switch_out_wwnr,
+ wakeup_wwnr,
+ event_max_wwnr
+};
+
+struct automaton_wwnr {
+ char *state_names[state_max_wwnr];
+ char *event_names[event_max_wwnr];
+ unsigned char function[state_max_wwnr][event_max_wwnr];
+ unsigned char initial_state;
+ bool final_states[state_max_wwnr];
+};
+
+struct automaton_wwnr automaton_wwnr = {
+ .state_names = {
+ "not_running",
+ "running"
+ },
+ .event_names = {
+ "switch_in",
+ "switch_out",
+ "wakeup"
+ },
+ .function = {
+ { running_wwnr, INVALID_STATE, not_running_wwnr },
+ { INVALID_STATE, not_running_wwnr, INVALID_STATE },
+ },
+ .initial_state = not_running_wwnr,
+ .final_states = { 1, 0 },
+};
diff --git a/tools/verification/models/wwnr.dot b/tools/verification/models/wwnr.dot
new file mode 100644
index 000000000000..1b206e83129c
--- /dev/null
+++ b/tools/verification/models/wwnr.dot
@@ -0,0 +1,16 @@
+digraph state_automaton {
+ {node [shape = plaintext, style=invis, label=""] "__init_not_running"};
+ {node [shape = ellipse] "not_running"};
+ {node [shape = plaintext] "not_running"};
+ {node [shape = plaintext] "running"};
+ "__init_not_running" -> "not_running";
+ "not_running" [label = "not_running", color = green3];
+ "not_running" -> "not_running" [ label = "wakeup" ];
+ "not_running" -> "running" [ label = "switch_in" ];
+ "running" [label = "running"];
+ "running" -> "not_running" [ label = "switch_out" ];
+ { rank = min ;
+ "__init_not_running";
+ "not_running";
+ }
+}
--
2.35.1

Subject: [PATCH V5 03/16] rv/include: Add helper functions for deterministic automata

Formally, a deterministic automaton, denoted by G, is defined as a
quintuple:

G = { X, E, f, x_0, X_m }

where:
- X is the set of states;
- E is the finite set of events;
- x_0 is the initial state;
- X_m (subset of X) is the set of marked states.
- f : X x E -> X $ is the transition function. It defines the
state transition in the occurrence of a event from E in
the state X. In the special case of deterministic automata,
the occurrence of the event in E in a state in X has a
deterministic next state from X.

An automaton can also be represented using a graphical format of
vertices (nodes) and edges. The open-source tool Graphviz can produce
this graphic format using the (textual) DOT language as the source code.

The dot2c tool presented in this paper:

DE OLIVEIRA, Daniel Bristot; CUCINOTTA, Tommaso; DE OLIVEIRA, Romulo
Silva. Efficient formal verification for the Linux kernel. In:
International Conference on Software Engineering and Formal Methods.
Springer, Cham, 2019. p. 315-332.

Translates a deterministic automaton in the DOT format into a C
source code representation that to be used for monitoring.

This header file implements helper functions to facilitate the usage
of the C output from dot2c/k for monitoring.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
include/rv/automata.h | 75 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 75 insertions(+)
create mode 100644 include/rv/automata.h

diff --git a/include/rv/automata.h b/include/rv/automata.h
new file mode 100644
index 000000000000..7125c91df607
--- /dev/null
+++ b/include/rv/automata.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+ *
+ * Deterministic automata helper functions, to be used with the automata
+ * models in C generated by the dot2k tool.
+ */
+
+/*
+ * DECLARE_AUTOMATA_HELPERS - define a set of helper functions for automata
+ *
+ * Define a set of helper functions for automata. The 'name' argument is used
+ * as suffix for the functions and data. These functions will handle automaton
+ * with data type 'type'.
+ */
+#define DECLARE_AUTOMATA_HELPERS(name, type) \
+ \
+/* \
+ * model_get_state_name_##name - return the (string) name of the given state \
+ */ \
+static char *model_get_state_name_##name(enum states_##name state) \
+{ \
+ if ((state < 0) || (state >= state_max_##name)) \
+ return "INVALID"; \
+ \
+ return automaton_##name.state_names[state]; \
+} \
+ \
+/* \
+ * model_get_event_name_##name - return the (string) name of the given event \
+ */ \
+static char *model_get_event_name_##name(enum events_##name event) \
+{ \
+ if ((event < 0) || (event >= event_max_##name)) \
+ return "INVALID"; \
+ \
+ return automaton_##name.event_names[event]; \
+} \
+ \
+/* \
+ * model_get_init_state_##name - return the automaton's initial state \
+ */ \
+static inline type model_get_init_state_##name(void) \
+{ \
+ return automaton_##name.initial_state; \
+} \
+ \
+/* \
+ * model_get_next_state_##name - process an automaton event occurrence \
+ * \
+ * Given the current state (curr_state) and the event (event), returns \
+ * the next state, or INVALID_STATE in case of error. \
+ */ \
+static inline type model_get_next_state_##name(enum states_##name curr_state, \
+ enum events_##name event) \
+{ \
+ if ((curr_state < 0) || (curr_state >= state_max_##name)) \
+ return INVALID_STATE; \
+ \
+ if ((event < 0) || (event >= event_max_##name)) \
+ return INVALID_STATE; \
+ \
+ return automaton_##name.function[curr_state][event]; \
+} \
+ \
+/* \
+ * model_is_final_state_##name - check if the given state is a final state \
+ */ \
+static inline bool model_is_final_state_##name(enum states_##name state) \
+{ \
+ if ((state < 0) || (state >= state_max_##name)) \
+ return 0; \
+ \
+ return automaton_##name.final_states[state]; \
+}
--
2.35.1

Subject: [PATCH V5 08/16] Documentation/rv: Add deterministic automaton documentation

Add documentation about deterministic automaton and its possible
representations (formal, graphic, .dot and C).

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
.../trace/rv/deterministic_automata.rst | 184 ++++++++++++++++++
Documentation/trace/rv/index.rst | 1 +
tools/verification/dot2/automata.py | 3 +
tools/verification/dot2/dot2c | 3 +
tools/verification/dot2/dot2c.py | 3 +
5 files changed, 194 insertions(+)
create mode 100644 Documentation/trace/rv/deterministic_automata.rst

diff --git a/Documentation/trace/rv/deterministic_automata.rst b/Documentation/trace/rv/deterministic_automata.rst
new file mode 100644
index 000000000000..8599cc01759d
--- /dev/null
+++ b/Documentation/trace/rv/deterministic_automata.rst
@@ -0,0 +1,184 @@
+Deterministic Automata
+======================
+
+Formally, a deterministic automaton, denoted by G, is defined as a quintuple:
+
+ *G* = { *X*, *E*, *f*, x\ :subscript:`0`, X\ :subscript:`m` }
+
+where:
+
+- *X* is the set of states;
+- *E* is the finite set of events;
+- x\ :subscript:`0` is the initial state;
+- X\ :subscript:`m` (subset of *X*) is the set of marked (or final) states.
+- *f* : *X* x *E* -> *X* $ is the transition function. It defines the state
+ transition in the occurrence of an event from *E* in the state *X*. In the
+ special case of deterministic automata, the occurrence of the event in *E*
+ in a state in *X* has a deterministic next state from *X*.
+
+For example, a given automaton named 'wip' (wakeup in preemptive) can
+be defined as:
+
+- *X* = { ``preemptive``, ``non_preemptive``}
+- *E* = { ``preempt_enable``, ``preempt_disable``, ``sched_waking``}
+- x\ :subscript:`0` = ``preemptive``
+- X\ :subscript:`m` = {``preemptive``}
+- *f* =
+ - *f*\ (``preemptive``, ``preempt_disable``) = ``non_preemptive``
+ - *f*\ (``non_preemptive``, ``sched_waking``) = ``non_preemptive``
+ - *f*\ (``non_preemptive``, ``preempt_enable``) = ``preemptive``
+
+One of the benefits of this formal definition is that it can be presented
+in multiple formats. For example, using a *graphical representation*, using
+vertices (nodes) and edges, which is very intuitive for *operating system*
+practitioners, without any loss.
+
+The previous 'wip' automaton can also be represented as::
+
+ preempt_enable
+ +---------------------------------+
+ v |
+ #============# preempt_disable +------------------+
+ --> H preemptive H -----------------> | non_preemptive |
+ #============# +------------------+
+ ^ |
+ | sched_waking |
+ +--------------+
+
+Deterministic Automaton in C
+----------------------------
+
+In the paper "Efficient formal verification for the Linux kernel",
+the authors present a simple way to represent an automaton in C that can
+be used as regular code in the Linux kernel.
+
+For example, the 'wip' automata can be presented as (augmented with comments)::
+
+ /* enum representation of X (set of states) to be used as index */
+ enum states {
+ preemptive = 0,
+ non_preemptive,
+ state_max
+ };
+
+ #define INVALID_STATE state_max
+
+ /* enum representation of E (set of events) to be used as index */
+ enum events {
+ preempt_disable = 0,
+ preempt_enable,
+ sched_waking,
+ event_max
+ };
+
+ struct automaton {
+ char *state_names[state_max]; // X: the set of states
+ char *event_names[event_max]; // E: the finite set of events
+ unsigned char function[state_max][event_max]; // f: transition function
+ unsigned char initial_state; // x_0: the initial state
+ bool final_states[state_max]; // X_m: the set of marked states
+ };
+
+ struct automaton aut = {
+ .state_names = {
+ "preemptive",
+ "non_preemptive"
+ },
+ .event_names = {
+ "preempt_disable",
+ "preempt_enable",
+ "sched_waking"
+ },
+ .function = {
+ { non_preemptive, INVALID_STATE, INVALID_STATE },
+ { INVALID_STATE, preemptive, non_preemptive },
+ },
+ .initial_state = preemptive,
+ .final_states = { 1, 0 },
+ };
+
+The *transition function* is represented as a matrix of states (lines) and
+events (columns), and so the function *f* : *X* x *E* -> *X* can be solved
+in O(1). For example::
+
+ next_state = automaton_wip.function[curr_state][event];
+
+Graphviz .dot format
+--------------------
+
+The Graphviz open-source tool can produce the graphical representation
+of an automaton using the (textual) DOT language as the source code.
+The DOT format is widely used and can be converted to many other formats.
+
+For example, this is the 'wip' model in DOT::
+
+ digraph state_automaton {
+ {node [shape = circle] "non_preemptive"};
+ {node [shape = plaintext, style=invis, label=""] "__init_preemptive"};
+ {node [shape = doublecircle] "preemptive"};
+ {node [shape = circle] "preemptive"};
+ "__init_preemptive" -> "preemptive";
+ "non_preemptive" [label = "non_preemptive"];
+ "non_preemptive" -> "non_preemptive" [ label = "sched_waking" ];
+ "non_preemptive" -> "preemptive" [ label = "preempt_enable" ];
+ "preemptive" [label = "preemptive"];
+ "preemptive" -> "non_preemptive" [ label = "preempt_disable" ];
+ { rank = min ;
+ "__init_preemptive";
+ "preemptive";
+ }
+ }
+
+This DOT format can be transformed into a bitmap or vectorial image
+using the dot utility, or into an ASCII art using graph-easy. For
+instance::
+
+ $ dot -Tsvg -o wip.svg wip.dot
+ $ graph-easy wip.dot > wip.txt
+
+dot2c
+-----
+
+dot2c is a utility that can parse a .dot file containing an automaton as
+in the example above and automatically convert it to the C representation
+presented in [3].
+
+For example, having the previous 'wip' model into a file named 'wip.dot',
+the following command will transform the .dot file into the C
+representation (previously shown) in the 'wip.h' file::
+
+ $ dot2c wip.dot > wip.h
+
+The 'wip.h' content is the code sample in section 'Deterministic Automaton
+in C'.
+
+Remarks
+-------
+
+The automata formalism allows modeling discrete event systems (DES) in
+multiple formats, suitable for different applications/users.
+
+For example, the formal description using set theory is better suitable
+for automata operations, while the graphical format for human interpretation;
+and computer languages for machine execution.
+
+References
+----------
+
+Many textbooks cover automata formalism. For a brief introduction see::
+
+ O'Regan, Gerard. Concise guide to software engineering. Springer,
+ Cham, 2017.
+
+For a detailed description, including operations, and application on Discrete
+Event Systems (DES), see::
+
+ Cassandras, Christos G., and Stephane Lafortune, eds. Introduction to discrete
+ event systems. Boston, MA: Springer US, 2008.
+
+For the C representation in kernel, see::
+
+ De Oliveira, Daniel Bristot; Cucinotta, Tommaso; De Oliveira, Romulo
+ Silva. Efficient formal verification for the Linux kernel. In:
+ International Conference on Software Engineering and Formal Methods.
+ Springer, Cham, 2019. p. 315-332.
diff --git a/Documentation/trace/rv/index.rst b/Documentation/trace/rv/index.rst
index b54e49b1d0de..013a41a410cf 100644
--- a/Documentation/trace/rv/index.rst
+++ b/Documentation/trace/rv/index.rst
@@ -7,3 +7,4 @@ Runtime Verification
:glob:

runtime-verification.rst
+ deterministic_automata.rst
diff --git a/tools/verification/dot2/automata.py b/tools/verification/dot2/automata.py
index f22e1dff19ce..baffeb960ff0 100644
--- a/tools/verification/dot2/automata.py
+++ b/tools/verification/dot2/automata.py
@@ -4,6 +4,9 @@
# Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
#
# Automata object: parse an automata in dot file digraph format into a python object
+#
+# For further information, see:
+# Documentation/trace/rv/deterministic_automata.rst

import ntpath

diff --git a/tools/verification/dot2/dot2c b/tools/verification/dot2/dot2c
index 8a8cd84bdfcf..3fe89ab88b65 100644
--- a/tools/verification/dot2/dot2c
+++ b/tools/verification/dot2/dot2c
@@ -9,6 +9,9 @@
# de Oliveira, D. B. and Cucinotta, T. and de Oliveira, R. S.
# "Efficient Formal Verification for the Linux Kernel." International
# Conference on Software Engineering and Formal Methods. Springer, Cham, 2019.
+#
+# For further information, see:
+# Documentation/trace/rv/deterministic_automata.rst

if __name__ == '__main__':
from dot2 import dot2c
diff --git a/tools/verification/dot2/dot2c.py b/tools/verification/dot2/dot2c.py
index bca902eec483..fa73353f7e56 100644
--- a/tools/verification/dot2/dot2c.py
+++ b/tools/verification/dot2/dot2c.py
@@ -9,6 +9,9 @@
# de Oliveira, D. B. and Cucinotta, T. and de Oliveira, R. S.
# "Efficient Formal Verification for the Linux Kernel." International
# Conference on Software Engineering and Formal Methods. Springer, Cham, 2019.
+#
+# For further information, see:
+# Documentation/trace/rv/deterministic_automata.rst

from dot2.automata import Automata

--
2.35.1

Subject: [PATCH V5 11/16] Documentation/rv: Add deterministic automata instrumentation documentation

Add the da_monitor_instrumentation.rst. It describes the basics
of RV monitor instrumentation.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
.../trace/rv/da_monitor_instrumentation.rst | 169 ++++++++++++++++++
Documentation/trace/rv/index.rst | 1 +
2 files changed, 170 insertions(+)
create mode 100644 Documentation/trace/rv/da_monitor_instrumentation.rst

diff --git a/Documentation/trace/rv/da_monitor_instrumentation.rst b/Documentation/trace/rv/da_monitor_instrumentation.rst
new file mode 100644
index 000000000000..7b83d6c7dbed
--- /dev/null
+++ b/Documentation/trace/rv/da_monitor_instrumentation.rst
@@ -0,0 +1,169 @@
+Deterministic Automata Instrumentation
+========================================
+
+The RV monitor file created by dot2k, with the name "$MODEL_NAME.c"
+includes a section dedicated to instrumentation.
+
+In the example of the wip.dot monitor created on [1], it will look like::
+
+ /*
+ * This is the instrumentation part of the monitor.
+ *
+ * This is the section where manual work is required. Here the kernel events
+ * are translated into model's event.
+ *
+ */
+ static void handle_preempt_disable(void *data, /* XXX: fill header */)
+ {
+ da_handle_event_wip(preempt_disable_wip);
+ }
+
+ static void handle_preempt_enable(void *data, /* XXX: fill header */)
+ {
+ da_handle_event_wip(preempt_enable_wip);
+ }
+
+ static void handle_sched_waking(void *data, /* XXX: fill header */)
+ {
+ da_handle_event_wip(sched_waking_wip);
+ }
+
+ static int start_wip(void)
+ {
+ int retval;
+
+ retval = da_monitor_init_wip();
+ if (retval)
+ return retval;
+
+ rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_disable);
+ rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_enable);
+ rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_sched_waking);
+
+ return 0;
+ }
+
+The comment at the top of the section explains the general idea: the
+instrumentation section translates *kernel events* into the *model's
+event*.
+
+Tracing callback functions
+-----------------------------
+
+The first three functions are the starting point of the callback *handler
+functions* for each of the three events from the wip model. The developer
+does not necessarily need to use them: they are just starting points.
+
+Using the example of::
+
+ void handle_preempt_disable(void *data, /* XXX: fill header */)
+ {
+ da_handle_event_wip(preempt_disable_wip);
+ }
+
+The preempt_disable event from the model connects directly to the
+preemptirq:preempt_disable. The preemptirq:preempt_disable event
+has the following signature, from include/trace/events/preemptirq.h::
+
+ TP_PROTO(unsigned long ip, unsigned long parent_ip)
+
+Hence, the handle_preempt_disable() function will look like::
+
+ void handle_preempt_disable(void *data, unsigned long ip, unsigned long parent_ip)
+
+In this case, the kernel event translates one to one with the automata
+event, and indeed, no other change is required for this function.
+
+The next handler function, handle_preempt_enable() has the same argument
+list from the handle_preempt_disable(). The difference is that the
+preempt_enable event will be used to synchronize the system to the model.
+
+Initially, the *model* is placed in the initial state. However, the *system*
+might or might not be in the initial state. The monitor cannot start
+processing events until it knows that the system has reached the initial state.
+Otherwise, the monitor and the system could be out-of-sync.
+
+Looking at the automata definition, it is possible to see that the system
+and the model are expected to return to the initial state after the
+preempt_enable execution. Hence, it can be used to synchronize the
+system and the model at the initialization of the monitoring section.
+
+The initialization is informed via a special handle function, the
+"da_handle_init_event_$(MONITOR)(event)", in this case::
+
+ da_handle_event_wip(preempt_disable_wip);
+
+So, the callback function will look like::
+
+ void handle_preempt_enable(void *data, unsigned long ip, unsigned long parent_ip)
+ {
+ da_handle_init_event_wip(preempt_enable_wip);
+ }
+
+Finally, the "handle_sched_waking()" will look like::
+
+ void handle_sched_waking(void *data, struct task_struct *task)
+ {
+ da_handle_event_wip(sched_waking_wip);
+ }
+
+And the explanation is left for the reader as an exercise.
+
+Start and Stop functions
+------------------------
+
+dot2k automatically creates two special functions::
+
+ start_$MODELNAME()
+ stop_$MODELNAME()
+
+These functions are called when the monitor is enabled and disabled,
+respectively.
+
+They should be used to *attach* and *detach* the instrumentation to the running
+system. The developer must add to the relative function all that is needed to
+*attach* and *detach* its monitor to the system.
+
+For the wip case, these functions were named::
+
+ start_wip()
+ stop_wip()
+
+But no change was required because: by default, these functions *attach* and
+*detach* the tracepoints_to_attach, which was enough for this case.
+
+Instrumentation helpers
+--------------------------
+
+To complete the instrumentation, the *handler functions* need to be attached to a
+kernel event, at the monitoring start phase.
+
+The RV interface also facilitates this step. For example, the macro "rv_attach_trace_probe()"
+is used to connect the wip model events to the relative kernel event. dot2k automatically
+adds "rv_attach_trace_probe()" function call for each model event in the start phase, as
+a suggestion.
+
+For example, from the wip sample model::
+
+ static int start_wip(void)
+ {
+ int retval;
+
+ retval = da_monitor_init_wip();
+ if (retval)
+ return retval;
+
+ rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_disable);
+ rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_enable);
+ rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_sched_waking);
+
+ return 0;
+ }
+
+The probes then need to be detached at the stop phase.
+
+[1] The wip model is presented in:
+ Documentation/trace/rv/deterministic_automata.rst
+
+ The wip monitor is presented in:
+ Documentation/trace/rv/da_monitor_synthesis.rst
diff --git a/Documentation/trace/rv/index.rst b/Documentation/trace/rv/index.rst
index 46d47f33052c..db2ae3f90b90 100644
--- a/Documentation/trace/rv/index.rst
+++ b/Documentation/trace/rv/index.rst
@@ -9,3 +9,4 @@ Runtime Verification
runtime-verification.rst
deterministic_automata.rst
da_monitor_synthesis.rst
+ da_monitor_instrumentation.rst
--
2.35.1

Subject: [PATCH V5 07/16] tools/rv: Add dot2c

dot2c is a tool that transforms an automata in the graphiviz .dot file
into an C representation of the automata.

usage: dot2c [-h] dot_file

dot2c: converts a .dot file into a C structure

positional arguments:
dot_file The dot file to be converted

optional arguments:
-h, --help show this help message and exit

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
tools/verification/dot2/Makefile | 21 +++
tools/verification/dot2/automata.py | 171 +++++++++++++++++++
tools/verification/dot2/dot2c | 23 +++
tools/verification/dot2/dot2c.py | 251 ++++++++++++++++++++++++++++
4 files changed, 466 insertions(+)
create mode 100644 tools/verification/dot2/Makefile
create mode 100644 tools/verification/dot2/automata.py
create mode 100644 tools/verification/dot2/dot2c
create mode 100644 tools/verification/dot2/dot2c.py

diff --git a/tools/verification/dot2/Makefile b/tools/verification/dot2/Makefile
new file mode 100644
index 000000000000..235d182f6b2c
--- /dev/null
+++ b/tools/verification/dot2/Makefile
@@ -0,0 +1,21 @@
+INSTALL=install
+
+prefix ?= /usr
+bindir ?= $(prefix)/bin
+mandir ?= $(prefix)/share/man
+miscdir ?= $(prefix)/share/dot2
+srcdir ?= $(prefix)/src
+
+PYLIB ?= $(shell python3 -c 'import sysconfig; print (sysconfig.get_path("purelib"))')
+
+.PHONY: all
+all:
+
+.PHONY: clean
+clean:
+
+.PHONY: install
+install:
+ $(INSTALL) automata.py -D -m 644 $(DESTDIR)$(PYLIB)/dot2/automata.py
+ $(INSTALL) dot2c.py -D -m 644 $(DESTDIR)$(PYLIB)/dot2/dot2c.py
+ $(INSTALL) dot2c -D -m 755 $(DESTDIR)$(bindir)/
diff --git a/tools/verification/dot2/automata.py b/tools/verification/dot2/automata.py
new file mode 100644
index 000000000000..f22e1dff19ce
--- /dev/null
+++ b/tools/verification/dot2/automata.py
@@ -0,0 +1,171 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+#
+# Automata object: parse an automata in dot file digraph format into a python object
+
+import ntpath
+
+class Automata:
+ """Automata class: Reads a dot file and part it as an automata.
+
+ Attributes:
+ dot_file: A dot file with an state_automaton definition.
+ """
+
+ invalid_state_str = "INVALID_STATE"
+
+ def __init__(self, file_path):
+ self.__dot_path = file_path
+ self.name = self.__get_model_name()
+ self.__dot_lines = self.__open_dot()
+ self.states, self.initial_state, self.final_states = self.__get_state_variables()
+ self.events = self.__get_event_variables()
+ self.function = self.__create_matrix()
+
+ def __get_model_name(self):
+ basename = ntpath.basename(self.__dot_path)
+ if basename.endswith(".dot") == False:
+ print("not a dot file")
+ raise Exception("not a dot file: %s" % self.__dot_path)
+
+ model_name = basename[0:-4]
+ if model_name.__len__() == 0:
+ raise Exception("not a dot file: %s" % self.__dot_path)
+
+ return model_name
+
+ def __open_dot(self):
+ cursor = 0
+ dot_lines = []
+ try:
+ dot_file = open(self.__dot_path)
+ except:
+ raise Exception("Cannot open the file: %s" % self.__dot_path)
+
+ dot_lines = dot_file.read().splitlines()
+ dot_file.close()
+
+ # checking the first line:
+ line = dot_lines[cursor].split()
+
+ if (line[0] != "digraph") and (line[1] != "state_automaton"):
+ raise Exception("Not a valid .dot format: %s" % self.__dot_path)
+ else:
+ cursor += 1
+ return dot_lines
+
+ def __get_cursor_begin_states(self):
+ cursor = 0
+ while self.__dot_lines[cursor].split()[0] != "{node":
+ cursor += 1
+ return cursor
+
+ def __get_cursor_begin_events(self):
+ cursor = 0
+ while self.__dot_lines[cursor].split()[0] != "{node":
+ cursor += 1
+ while self.__dot_lines[cursor].split()[0] == "{node":
+ cursor += 1
+ # skip initial state transition
+ cursor += 1
+ return cursor
+
+ def __get_state_variables(self):
+ # wait for node declaration
+ states = []
+ final_states = []
+
+ has_final_states = False
+ cursor = self.__get_cursor_begin_states()
+
+ # process nodes
+ while self.__dot_lines[cursor].split()[0] == "{node":
+ line = self.__dot_lines[cursor].split()
+ raw_state = line[-1]
+
+ # "enabled_fired"}; -> enabled_fired
+ state = raw_state.replace('"', '').replace('};', '').replace(',','_')
+ if state[0:7] == "__init_":
+ initial_state = state[7:]
+ else:
+ states.append(state)
+ if self.__dot_lines[cursor].__contains__("doublecircle") == True:
+ final_states.append(state)
+ has_final_states = True
+
+ if self.__dot_lines[cursor].__contains__("ellipse") == True:
+ final_states.append(state)
+ has_final_states = True
+
+ cursor += 1
+
+ states = sorted(set(states))
+ states.remove(initial_state)
+
+ # Insert the initial state at the bein og the states
+ states.insert(0, initial_state)
+
+ if has_final_states == False:
+ final_states.append(initial_state)
+
+ return states, initial_state, final_states
+
+ def __get_event_variables(self):
+ # here we are at the begin of transitions, take a note, we will return later.
+ cursor = self.__get_cursor_begin_events()
+
+ events = []
+ while self.__dot_lines[cursor][1] == '"':
+ # transitions have the format:
+ # "all_fired" -> "both_fired" [ label = "disable_irq" ];
+ # ------------ event is here ------------^^^^^
+ if self.__dot_lines[cursor].split()[1] == "->":
+ line = self.__dot_lines[cursor].split()
+ event = line[-2].replace('"','')
+
+ # when a transition has more than one lables, they are like this
+ # "local_irq_enable\nhw_local_irq_enable_n"
+ # so split them.
+
+ event = event.replace("\\n", " ")
+ for i in event.split():
+ events.append(i)
+ cursor += 1
+
+ return sorted(set(events))
+
+ def __create_matrix(self):
+ # transform the array into a dictionary
+ events = self.events
+ states = self.states
+ events_dict = {}
+ states_dict = {}
+ nr_event = 0
+ for event in events:
+ events_dict[event] = nr_event
+ nr_event += 1
+
+ nr_state = 0
+ for state in states:
+ states_dict[state] = nr_state
+ nr_state += 1
+
+ # declare the matrix....
+ matrix = [[ self.invalid_state_str for x in range(nr_event)] for y in range(nr_state)]
+
+ # and we are back! Let's fill the matrix
+ cursor = self.__get_cursor_begin_events()
+
+ while self.__dot_lines[cursor][1] == '"':
+ if self.__dot_lines[cursor].split()[1] == "->":
+ line = self.__dot_lines[cursor].split()
+ origin_state = line[0].replace('"','').replace(',','_')
+ dest_state = line[2].replace('"','').replace(',','_')
+ possible_events = line[-2].replace('"','').replace("\\n", " ")
+ for event in possible_events.split():
+ matrix[states_dict[origin_state]][events_dict[event]] = dest_state
+ cursor += 1
+
+ return matrix
diff --git a/tools/verification/dot2/dot2c b/tools/verification/dot2/dot2c
new file mode 100644
index 000000000000..8a8cd84bdfcf
--- /dev/null
+++ b/tools/verification/dot2/dot2c
@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+#
+# dot2c: parse an automata in dot file digraph format into a C
+#
+# This program was written in the development of this paper:
+# de Oliveira, D. B. and Cucinotta, T. and de Oliveira, R. S.
+# "Efficient Formal Verification for the Linux Kernel." International
+# Conference on Software Engineering and Formal Methods. Springer, Cham, 2019.
+
+if __name__ == '__main__':
+ from dot2 import dot2c
+ import argparse
+ import sys
+
+ parser = argparse.ArgumentParser(description='dot2c: converts a .dot file into a C structure')
+ parser.add_argument('dot_file', help='The dot file to be converted')
+
+ args = parser.parse_args()
+ d = dot2c.Dot2c(args.dot_file)
+ d.print_model_classic()
diff --git a/tools/verification/dot2/dot2c.py b/tools/verification/dot2/dot2c.py
new file mode 100644
index 000000000000..bca902eec483
--- /dev/null
+++ b/tools/verification/dot2/dot2c.py
@@ -0,0 +1,251 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+#
+# dot2c: parse an automata in dot file digraph format into a C
+#
+# This program was written in the development of this paper:
+# de Oliveira, D. B. and Cucinotta, T. and de Oliveira, R. S.
+# "Efficient Formal Verification for the Linux Kernel." International
+# Conference on Software Engineering and Formal Methods. Springer, Cham, 2019.
+
+from dot2.automata import Automata
+
+class Dot2c(Automata):
+ enum_suffix = ""
+ enum_states_def = "states"
+ enum_events_def = "events"
+ struct_automaton_def = "automaton"
+ var_automaton_def = "aut"
+
+ def __init__(self, file_path):
+ super().__init__(file_path)
+ self.line_length = 100
+
+ def __buff_to_string(self, buff):
+ string = ""
+
+ for line in buff:
+ string = string + line + "\n"
+
+ # cut off the last \n
+ return string[:-1]
+
+ def __get_enum_states_content(self):
+ buff = []
+ buff.append("\t%s%s = 0," % (self.initial_state, self.enum_suffix))
+ for state in self.states:
+ if state != self.initial_state:
+ buff.append("\t%s%s," % (state, self.enum_suffix))
+ buff.append("\tstate_max%s" % (self.enum_suffix))
+
+ return buff
+
+ def get_enum_states_string(self):
+ buff = self.__get_enum_states_content()
+ return self.__buff_to_string(buff)
+
+ def format_states_enum(self):
+ buff = []
+ buff.append("enum %s {" % self.enum_states_def)
+ buff.append(self.get_enum_states_string())
+ buff.append("};\n")
+
+ return buff
+
+ def __get_enum_events_content(self):
+ buff = []
+ first = True
+ for event in self.events:
+ if first:
+ buff.append("\t%s%s = 0," % (event, self.enum_suffix))
+ first = False
+ else:
+ buff.append("\t%s%s," % (event, self.enum_suffix))
+
+ buff.append("\tevent_max%s" % self.enum_suffix)
+
+ return buff
+
+ def get_enum_events_string(self):
+ buff = self.__get_enum_events_content()
+ return self.__buff_to_string(buff)
+
+ def format_events_enum(self):
+ buff = []
+ buff.append("enum %s {" % self.enum_events_def)
+ buff.append(self.get_enum_events_string())
+ buff.append("};\n")
+
+ return buff
+
+ def get_minimun_type(self):
+ min_type = "unsigned char"
+
+ if self.states.__len__() > 255:
+ min_type = "unsigned short"
+
+ if self.states.__len__() > 65535:
+ min_type = "unsigned int"
+
+ if self.states.__len__() > 1000000:
+ raise Exception("Too many states: %d" % self.states.__len__())
+
+ return min_type
+
+ def format_automaton_definition(self):
+ min_type = self.get_minimun_type()
+ buff = []
+ buff.append("struct %s {" % self.struct_automaton_def)
+ buff.append("\tchar *state_names[state_max%s];" % (self.enum_suffix))
+ buff.append("\tchar *event_names[event_max%s];" % (self.enum_suffix))
+ buff.append("\t%s function[state_max%s][event_max%s];" % (min_type, self.enum_suffix, self.enum_suffix))
+ buff.append("\t%s initial_state;" % min_type)
+ buff.append("\tbool final_states[state_max%s];" % (self.enum_suffix))
+ buff.append("};\n")
+ return buff
+
+ def format_aut_init_header(self):
+ buff = []
+ buff.append("struct %s %s = {" % (self.struct_automaton_def, self.var_automaton_def))
+ return buff
+
+ def __get_string_vector_per_line_content(self, buff):
+ first = True
+ string = ""
+ for entry in buff:
+ if first:
+ string = string + "\t\t\"" + entry
+ first = False;
+ else:
+ string = string + "\",\n\t\t\"" + entry
+ string = string + "\""
+
+ return string
+
+ def get_aut_init_events_string(self):
+ return self.__get_string_vector_per_line_content(self.events)
+
+ def get_aut_init_states_string(self):
+ return self.__get_string_vector_per_line_content(self.states)
+
+ def format_aut_init_events_string(self):
+ buff = []
+ buff.append("\t.event_names = {")
+ buff.append(self.get_aut_init_events_string())
+ buff.append("\t},")
+ return buff
+
+ def format_aut_init_states_string(self):
+ buff = []
+ buff.append("\t.state_names = {")
+ buff.append(self.get_aut_init_states_string())
+ buff.append("\t},")
+
+ return buff
+
+ def __get_max_strlen_of_states(self):
+ max_state_name = max(self.states, key = len).__len__()
+ return max(max_state_name, self.invalid_state_str.__len__())
+
+ def __get_state_string_length(self):
+ maxlen = self.__get_max_strlen_of_states() + self.enum_suffix.__len__()
+ return "%" + str(maxlen) + "s"
+
+ def get_aut_init_function(self):
+ nr_states = self.states.__len__()
+ nr_events = self.events.__len__()
+ buff = []
+
+ strformat = self.__get_state_string_length()
+
+ for x in range(nr_states):
+ line = "\t\t{ "
+ for y in range(nr_events):
+ next_state = self.function[x][y]
+ if next_state != self.invalid_state_str:
+ next_state = self.function[x][y] + self.enum_suffix
+
+ if y != nr_events-1:
+ line = line + strformat % next_state + ", "
+ else:
+ line = line + strformat % next_state + " },"
+ buff.append(line)
+
+ return self.__buff_to_string(buff)
+
+ def format_aut_init_function(self):
+ buff = []
+ buff.append("\t.function = {")
+ buff.append(self.get_aut_init_function())
+ buff.append("\t},")
+
+ return buff
+
+ def get_aut_init_initial_state(self):
+ return self.initial_state
+
+ def format_aut_init_initial_state(self):
+ buff = []
+ initial_state = self.get_aut_init_initial_state()
+ buff.append("\t.initial_state = " + initial_state + self.enum_suffix + ",")
+
+ return buff
+
+ def get_aut_init_final_states(self):
+ line = ""
+ first = True
+ for state in self.states:
+ if first == False:
+ line = line + ', '
+ else:
+ first = False
+
+ if self.final_states.__contains__(state):
+ line = line + '1'
+ else:
+ line = line + '0'
+ return line
+
+ def format_aut_init_final_states(self):
+ buff = []
+ buff.append("\t.final_states = { %s }," % self.get_aut_init_final_states())
+
+ return buff
+
+ def __get_automaton_initialization_footer_string(self):
+ footer = "};\n"
+ return footer
+
+ def format_aut_init_footer(self):
+ buff = []
+ buff.append(self.__get_automaton_initialization_footer_string())
+
+ return buff
+
+ def format_invalid_state(self):
+ buff = []
+ buff.append("#define %s state_max%s\n" % (self.invalid_state_str, self.enum_suffix))
+
+ return buff
+
+ def format_model(self):
+ buff = []
+ buff += self.format_states_enum()
+ buff += self.format_invalid_state()
+ buff += self.format_events_enum()
+ buff += self.format_automaton_definition()
+ buff += self.format_aut_init_header()
+ buff += self.format_aut_init_states_string()
+ buff += self.format_aut_init_events_string()
+ buff += self.format_aut_init_function()
+ buff += self.format_aut_init_initial_state()
+ buff += self.format_aut_init_final_states()
+ buff += self.format_aut_init_footer()
+
+ return buff
+
+ def print_model_classic(self):
+ buff = self.format_model()
+ print(self.__buff_to_string(buff))
--
2.35.1

Subject: [PATCH V5 04/16] rv/include: Add deterministic automata monitor definition via C macros

In Linux terms, the runtime verification monitors are encapsulated
inside the "RV monitor" abstraction. The "RV monitor" includes a set
of instances of the monitor (per-cpu monitor, per-task monitor, and
so on), the helper functions that glue the monitor to the system
reference model, and the trace output as a reaction for event parsing
and exceptions, as depicted below:

Linux +----- RV Monitor ----------------------------------+ Formal
Realm | | Realm
+-------------------+ +----------------+ +-----------------+
| Linux kernel | | Monitor | | Reference |
| Tracing | -> | Instance(s) | <- | Model |
| (instrumentation) | | (verification) | | (specification) |
+-------------------+ +----------------+ +-----------------+
| | |
| V |
| +----------+ |
| | Reaction | |
| +--+--+--+-+ |
| | | | |
| | | +-> trace output ? |
+------------------------|--|----------------------+
| +----> panic ?
+-------> <user-specified>

Add the rv/da_monitor.h, enabling automatic code generation for the
*Monitor Instance(s)* using C macros, and code to support it.

The benefits of the usage of macro for monitor synthesis are 3-fold as it:

- Reduces the code duplication;
- Facilitates the bug fix/improvement;
- Avoids the case of developers changing the core of the monitor code
to manipulate the model in a (let's say) non-standard way.

This initial implementation presents three different types of monitor
instances:

- DECLARE_DA_MON_GLOBAL(name, type)
- DECLARE_DA_MON_PER_CPU(name, type)
- DECLARE_DA_MON_PER_TASK(name, type)

The first declares the functions for a global deterministic automata monitor,
the second for monitors with per-cpu instances, and the third with per-task
instances.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
include/linux/rv.h | 2 +
include/rv/da_monitor.h | 521 ++++++++++++++++++++++++++++++++++++++
include/rv/rv.h | 9 +
include/trace/events/rv.h | 120 +++++++++
kernel/fork.c | 14 +
kernel/trace/rv/Kconfig | 14 +
kernel/trace/rv/rv.c | 5 +
7 files changed, 685 insertions(+)
create mode 100644 include/rv/da_monitor.h
create mode 100644 include/trace/events/rv.h

diff --git a/include/linux/rv.h b/include/linux/rv.h
index 88d28d207f3a..bdefdff12a1f 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -7,6 +7,8 @@
#ifndef _LINUX_RV_H
#define _LINUX_RV_H

+#define MAX_DA_NAME_LEN 24
+
struct rv_reactor {
char *name;
char *description;
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
new file mode 100644
index 000000000000..d21045e6c5fc
--- /dev/null
+++ b/include/rv/da_monitor.h
@@ -0,0 +1,521 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+ *
+ * Deterministic automata (DA) monitor functions, to be used together
+ * with automata models in C generated by the dot2k tool.
+ *
+ * The dot2k tool is available at tools/verification/dot2k/
+ */
+
+#include <rv/automata.h>
+#include <linux/rv.h>
+
+/*
+ * Generic helpers for all types of deterministic automata monitors.
+ */
+#define DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+static char REACT_MSG[1024]; \
+ \
+static inline char *format_react_msg(type curr_state, type event) \
+{ \
+ snprintf(REACT_MSG, 1024, \
+ "rv: monitor %s does not allow event %s on state %s\n", \
+ #name, \
+ model_get_event_name_##name(event), \
+ model_get_state_name_##name(curr_state)); \
+ return REACT_MSG; \
+} \
+ \
+static void cond_react(char *msg) \
+{ \
+ if (rv_##name.react) \
+ rv_##name.react(msg); \
+} \
+ \
+/* \
+ * da_monitor_reset_##name - reset a monitor and setting it to init state \
+ */ \
+static inline void da_monitor_reset_##name(struct da_monitor *da_mon) \
+{ \
+ da_mon->monitoring = 0; \
+ da_mon->curr_state = model_get_init_state_##name(); \
+} \
+ \
+/* \
+ * da_monitor_curr_state_##name - return the current state \
+ */ \
+static inline type da_monitor_curr_state_##name(struct da_monitor *da_mon) \
+{ \
+ return da_mon->curr_state; \
+} \
+ \
+/* \
+ * da_monitor_set_state_##name - set the new current state \
+ */ \
+static inline void \
+da_monitor_set_state_##name(struct da_monitor *da_mon, enum states_##name state)\
+{ \
+ da_mon->curr_state = state; \
+} \
+ \
+/* \
+ * da_monitor_start_##name - start monitoring \
+ * \
+ * The monitor will ignore all events until monitoring is set to true. This \
+ * function needs to be called to tell the monitor to start monitoring. \
+ */ \
+static inline void da_monitor_start_##name(struct da_monitor *da_mon) \
+{ \
+ da_mon->monitoring = 1; \
+} \
+ \
+/* \
+ * da_monitoring_##name - returns true if the monitor is processing events \
+ */ \
+static inline bool da_monitoring_##name(struct da_monitor *da_mon) \
+{ \
+ return da_mon->monitoring; \
+}
+
+
+/*
+ * Event handler for implicit monitors. Implicit monitor is the one which the
+ * handler does not need to specify which da_monitor to manipulate. Examples
+ * of implicit monitor are the per_cpu or the global ones.
+ */
+#define DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
+static inline bool \
+da_event_##name(struct da_monitor *da_mon, enum events_##name event) \
+{ \
+ type curr_state = da_monitor_curr_state_##name(da_mon); \
+ type next_state = model_get_next_state_##name(curr_state, event); \
+ \
+ if (next_state != INVALID_STATE) { \
+ da_monitor_set_state_##name(da_mon, next_state); \
+ \
+ trace_event_##name(model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event), \
+ model_get_state_name_##name(next_state), \
+ model_is_final_state_##name(next_state)); \
+ \
+ return true; \
+ } \
+ \
+ if (reacting_on) \
+ cond_react(format_react_msg(curr_state, event)); \
+ \
+ trace_error_##name(model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event)); \
+ \
+ return false; \
+} \
+
+/*
+ * Event handler for per_task monitors.
+ */
+#define DECLARE_DA_MON_MODEL_HANDLER_PER_TASK(name, type) \
+static inline type \
+da_event_##name(struct da_monitor *da_mon, struct task_struct *tsk, \
+ enum events_##name event) \
+{ \
+ type curr_state = da_monitor_curr_state_##name(da_mon); \
+ type next_state = model_get_next_state_##name(curr_state, event); \
+ \
+ if (next_state != INVALID_STATE) { \
+ da_monitor_set_state_##name(da_mon, next_state); \
+ \
+ trace_event_##name(tsk->pid, \
+ model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event), \
+ model_get_state_name_##name(next_state), \
+ model_is_final_state_##name(next_state)); \
+ \
+ return true; \
+ } \
+ \
+ if (reacting_on) \
+ cond_react(format_react_msg(curr_state, event)); \
+ \
+ trace_error_##name(tsk->pid, \
+ model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event)); \
+ \
+ return false; \
+}
+
+/*
+ * Functions to define, init and get a global monitor.
+ */
+#define DECLARE_DA_MON_INIT_GLOBAL(name, type) \
+ \
+/* \
+ * global monitor (a single variable) \
+ */ \
+static struct da_monitor da_mon_##name; \
+ \
+/* \
+ * da_get_monitor_##name - return the global monitor address \
+ */ \
+static struct da_monitor *da_get_monitor_##name(void) \
+{ \
+ return &da_mon_##name; \
+} \
+ \
+/* \
+ * da_monitor_reset_all_##name - reset the single monitor \
+ */ \
+static void da_monitor_reset_all_##name(void) \
+{ \
+ da_monitor_reset_##name(&da_mon_##name); \
+} \
+ \
+/* \
+ * da_monitor_init_##name - initialize a monitor \
+ */ \
+static inline int da_monitor_init_##name(void) \
+{ \
+ struct da_monitor *da_mon = &da_mon_##name; \
+ da_mon->curr_state = model_get_init_state_##name(); \
+ da_mon->monitoring = 0; \
+ return 0; \
+} \
+ \
+/* \
+ * da_monitor_destroy_##name - destroy the monitor \
+ */ \
+static inline void da_monitor_destroy_##name(void) \
+{ \
+ return; \
+}
+
+/*
+ * Functions to define, init and get a per-cpu monitor.
+ */
+#define DECLARE_DA_MON_INIT_PER_CPU(name, type) \
+ \
+/* \
+ * per-cpu monitor variables \
+ */ \
+DEFINE_PER_CPU(struct da_monitor, da_mon_##name); \
+ \
+/* \
+ * da_get_monitor_##name - return current CPU monitor address \
+ */ \
+static struct da_monitor *da_get_monitor_##name(void) \
+{ \
+ return this_cpu_ptr(&da_mon_##name); \
+} \
+ \
+/* \
+ * da_monitor_reset_all_##name - reset all CPUs' monitor \
+ */ \
+static void da_monitor_reset_all_##name(void) \
+{ \
+ struct da_monitor *da_mon; \
+ int cpu; \
+ for_each_cpu(cpu, cpu_online_mask) { \
+ da_mon = per_cpu_ptr(&da_mon_##name, cpu); \
+ da_monitor_reset_##name(da_mon); \
+ } \
+} \
+ \
+/* \
+ * da_monitor_init_##name - initialize all CPUs' monitor \
+ */ \
+static inline int da_monitor_init_##name(void) \
+{ \
+ struct da_monitor *da_mon; \
+ int cpu; \
+ for_each_cpu(cpu, cpu_online_mask) { \
+ da_mon = per_cpu_ptr(&da_mon_##name, cpu); \
+ da_mon->curr_state = model_get_init_state_##name(); \
+ da_mon->monitoring = 0; \
+ } \
+ return 0; \
+} \
+ \
+/* \
+ * da_monitor_destroy_##name - destroy the monitor \
+ */ \
+static inline void da_monitor_destroy_##name(void) \
+{ \
+ return; \
+}
+
+/*
+ * Functions to define, init and get a per-task monitor.
+ */
+#define DECLARE_DA_MON_INIT_PER_TASK(name, type) \
+ \
+/* \
+ * The per-task monitor is stored a vector in the task struct. This variable \
+ * stores the position on the vector reserved for this monitor. \
+ */ \
+static int task_mon_slot_##name = RV_PER_TASK_MONITOR_INIT; \
+ \
+/* \
+ * da_get_monitor_##name - return the monitor in the allocated slot for tsk \
+ */ \
+static inline struct da_monitor *da_get_monitor_##name(struct task_struct *tsk) \
+{ \
+ return &tsk->rv[task_mon_slot_##name].da_mon; \
+} \
+ \
+static void da_monitor_reset_all_##name(void) \
+{ \
+ struct task_struct *g, *p; \
+ \
+ read_lock(&tasklist_lock); \
+ for_each_process_thread(g, p) \
+ da_monitor_reset_##name(da_get_monitor_##name(p)); \
+ read_unlock(&tasklist_lock); \
+} \
+ \
+/* \
+ * da_monitor_init_##name - initialize the per-task monitor \
+ * \
+ * Try to allocate a slot in the task's vector of monitors. If there \
+ * is an available slot, use it and reset all task's monitor. \
+ */ \
+static int da_monitor_init_##name(void) \
+{ \
+ struct da_monitor *da_mon; \
+ struct task_struct *g, *p; \
+ int retval; \
+ \
+ retval = get_task_monitor_slot(); \
+ if (retval < 0) \
+ return retval; \
+ \
+ task_mon_slot_##name = retval; \
+ \
+ read_lock(&tasklist_lock); \
+ for_each_process_thread(g, p) { \
+ da_mon = da_get_monitor_##name(p); \
+ da_mon->curr_state = model_get_init_state_##name(); \
+ da_mon->monitoring = 0; \
+ } \
+ read_unlock(&tasklist_lock); \
+ \
+ return 0; \
+} \
+ \
+/* \
+ * da_monitor_destroy_##name - return the allocated slot \
+ */ \
+static inline void da_monitor_destroy_##name(void) \
+{ \
+ if (task_mon_slot_##name == RV_PER_TASK_MONITOR_INIT) { \
+ WARN_ONCE(1, "Disabling a disabled monitor: " #name); \
+ return; \
+ } \
+ put_task_monitor_slot(task_mon_slot_##name); \
+ return; \
+}
+
+/*
+ * Handle event for implicit monitor: da_get_monitor_##name() will figure out
+ * the monitor.
+ */
+#define DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type) \
+ \
+static inline void __da_handle_event_##name(struct da_monitor *da_mon, \
+ enum events_##name event) \
+{ \
+ int retval; \
+ \
+ /* global switch */ \
+ if (unlikely(!monitoring_on)) \
+ return; \
+ \
+ /* monitor enabled */ \
+ if (unlikely(!rv_##name.enabled)) \
+ return; \
+ \
+ /* monitor is actually monitoring */ \
+ if (unlikely(!da_monitoring_##name(da_mon))) \
+ return; \
+ \
+ retval = da_event_##name(da_mon, event); \
+ \
+ if (!retval) \
+ da_monitor_reset_##name(da_mon); \
+} \
+ \
+/* \
+ * da_handle_event_##name - handle an event \
+ */ \
+static inline void da_handle_event_##name(enum events_##name event) \
+{ \
+ struct da_monitor *da_mon = da_get_monitor_##name(); \
+ __da_handle_event_##name(da_mon, event); \
+} \
+ \
+/* \
+ * da_handle_init_event_##name - start monitoring or handle event \
+ * \
+ * This function is used notify the monitor that the system is returning \
+ * to the initial state, so the monitor can start monitoring in the next event. \
+ * Thus: \
+ * \
+ * If the monitor already started, handle the event. \
+ * If the monitor did not start yet, start the monitor but skip the event. \
+ */ \
+static inline bool da_handle_init_event_##name(enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (unlikely(!rv_##name.enabled)) \
+ return false; \
+ \
+ da_mon = da_get_monitor_##name(); \
+ \
+ if (unlikely(!da_monitoring_##name(da_mon))) { \
+ da_monitor_start_##name(da_mon); \
+ return false; \
+ } \
+ \
+ __da_handle_event_##name(da_mon, event); \
+ \
+ return true; \
+} \
+ \
+/* \
+ * da_handle_init_run_event_##name - start monitoring and handle event \
+ * \
+ * This function is used notify the monitor that the system is in the \
+ * initial state, so the monitor can start monitoring and handling event. \
+ */ \
+static inline bool da_handle_init_run_event_##name(enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (unlikely(!rv_##name.enabled)) \
+ return false; \
+ \
+ da_mon = da_get_monitor_##name(); \
+ \
+ if (unlikely(!da_monitoring_##name(da_mon))) \
+ da_monitor_start_##name(da_mon); \
+ \
+ __da_handle_event_##name(da_mon, event); \
+ \
+ return true; \
+}
+
+/*
+ * Handle event for per task.
+ */
+#define DECLARE_DA_MON_MONITOR_HANDLER_PER_TASK(name, type) \
+ \
+static inline void \
+__da_handle_event_##name(struct da_monitor *da_mon, struct task_struct *tsk, \
+ enum events_##name event) \
+{ \
+ int retval; \
+ \
+ /* global switch */ \
+ if (unlikely(!monitoring_on)) \
+ return; \
+ \
+ /* monitor enabled */ \
+ if (unlikely(!rv_##name.enabled)) \
+ return; \
+ \
+ /* monitor is actually monitoring */ \
+ if (unlikely(!da_monitoring_##name(da_mon))) \
+ return; \
+ \
+ retval = da_event_##name(da_mon, tsk, event); \
+ \
+ if (!retval) \
+ da_monitor_reset_##name(da_mon); \
+} \
+ \
+/* \
+ * da_handle_event_##name - handle an event \
+ */ \
+static inline void \
+da_handle_event_##name(struct task_struct *tsk, enum events_##name event) \
+{ \
+ struct da_monitor *da_mon = da_get_monitor_##name(tsk); \
+ __da_handle_event_##name(da_mon, tsk, event); \
+} \
+ \
+/* \
+ * da_handle_init_event_##name - start monitoring or handle event \
+ * \
+ * This function is used notify the monitor that the system is returning \
+ * to the initial state, so the monitor can start monitoring in the next event. \
+ * Thus: \
+ * \
+ * If the monitor already started, handle the event. \
+ * If the monitor did not start yet, start the monitor but skip the event. \
+ */ \
+static inline bool \
+da_handle_init_event_##name(struct task_struct *tsk, enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (unlikely(!rv_##name.enabled)) \
+ return false; \
+ \
+ da_mon = da_get_monitor_##name(tsk); \
+ \
+ if (unlikely(!da_monitoring_##name(da_mon))) { \
+ da_monitor_start_##name(da_mon); \
+ return false; \
+ } \
+ \
+ __da_handle_event_##name(da_mon, tsk, event); \
+ \
+ return true; \
+}
+
+/*
+ * Entry point for the global monitor.
+ */
+#define DECLARE_DA_MON_GLOBAL(name, type) \
+ \
+DECLARE_AUTOMATA_HELPERS(name, type) \
+ \
+DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+ \
+DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
+ \
+DECLARE_DA_MON_INIT_GLOBAL(name, type) \
+ \
+DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type)
+
+
+/*
+ * Entry point for the per-cpu monitor.
+ */
+#define DECLARE_DA_MON_PER_CPU(name, type) \
+ \
+DECLARE_AUTOMATA_HELPERS(name, type) \
+ \
+DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+ \
+DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
+ \
+DECLARE_DA_MON_INIT_PER_CPU(name, type) \
+ \
+DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type)
+
+
+/*
+ * Entry point for the per-task monitor.
+ */
+#define DECLARE_DA_MON_PER_TASK(name, type) \
+ \
+DECLARE_AUTOMATA_HELPERS(name, type) \
+ \
+DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+ \
+DECLARE_DA_MON_MODEL_HANDLER_PER_TASK(name, type) \
+ \
+DECLARE_DA_MON_INIT_PER_TASK(name, type) \
+ \
+DECLARE_DA_MON_MONITOR_HANDLER_PER_TASK(name, type)
diff --git a/include/rv/rv.h b/include/rv/rv.h
index 27a108881d35..b0658cdc53d9 100644
--- a/include/rv/rv.h
+++ b/include/rv/rv.h
@@ -3,6 +3,14 @@
#ifndef _RV_RV_H
#define _RV_RV_H

+/*
+ * Deterministic automaton per-object variables.
+ */
+struct da_monitor {
+ bool monitoring;
+ int curr_state;
+};
+
/*
* Per-task RV monitors count. Nowadays fixed in RV_PER_TASK_MONITORS.
* If we find justification for more monitors, we can think about
@@ -16,6 +24,7 @@
* Futher monitor types are expected, so make this a union.
*/
union rv_task_monitor {
+ struct da_monitor da_mon;
};

int get_task_monitor_slot(void);
diff --git a/include/trace/events/rv.h b/include/trace/events/rv.h
new file mode 100644
index 000000000000..480aac18f403
--- /dev/null
+++ b/include/trace/events/rv.h
@@ -0,0 +1,120 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rv
+
+#if !defined(_TRACE_RV_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_RV_H
+
+#include <linux/rv.h>
+#include <linux/tracepoint.h>
+
+#ifdef CONFIG_DA_MON_EVENTS_IMPLICIT
+DECLARE_EVENT_CLASS(event_da_monitor,
+
+ TP_PROTO(char *state, char *event, char *next_state, bool final_state),
+
+ TP_ARGS(state, event, next_state, final_state),
+
+ TP_STRUCT__entry(
+ __array( char, state, MAX_DA_NAME_LEN )
+ __array( char, event, MAX_DA_NAME_LEN )
+ __array( char, next_state, MAX_DA_NAME_LEN )
+ __field( bool, final_state )
+ ),
+
+ TP_fast_assign(
+ memcpy(__entry->state, state, MAX_DA_NAME_LEN);
+ memcpy(__entry->event, event, MAX_DA_NAME_LEN);
+ memcpy(__entry->next_state, next_state, MAX_DA_NAME_LEN);
+ __entry->final_state = final_state;
+ ),
+
+ TP_printk("%s x %s -> %s %s",
+ __entry->state,
+ __entry->event,
+ __entry->next_state,
+ __entry->final_state ? "(final)" : "")
+);
+
+DECLARE_EVENT_CLASS(error_da_monitor,
+
+ TP_PROTO(char *state, char *event),
+
+ TP_ARGS(state, event),
+
+ TP_STRUCT__entry(
+ __array( char, state, MAX_DA_NAME_LEN )
+ __array( char, event, MAX_DA_NAME_LEN )
+ ),
+
+ TP_fast_assign(
+ memcpy(__entry->state, state, MAX_DA_NAME_LEN);
+ memcpy(__entry->event, event, MAX_DA_NAME_LEN);
+ ),
+
+ TP_printk("event %s not expected in the state %s",
+ __entry->event,
+ __entry->state)
+);
+#endif /* CONFIG_DA_MON_EVENTS_IMPLICIT */
+
+#ifdef CONFIG_DA_MON_EVENTS_ID
+DECLARE_EVENT_CLASS(event_da_monitor_id,
+
+ TP_PROTO(int id, char *state, char *event, char *next_state, bool final_state),
+
+ TP_ARGS(id, state, event, next_state, final_state),
+
+ TP_STRUCT__entry(
+ __field( int, id )
+ __array( char, state, MAX_DA_NAME_LEN )
+ __array( char, event, MAX_DA_NAME_LEN )
+ __array( char, next_state, MAX_DA_NAME_LEN )
+ __field( bool, final_state )
+ ),
+
+ TP_fast_assign(
+ memcpy(__entry->state, state, MAX_DA_NAME_LEN);
+ memcpy(__entry->event, event, MAX_DA_NAME_LEN);
+ memcpy(__entry->next_state, next_state, MAX_DA_NAME_LEN);
+ __entry->id = id;
+ __entry->final_state = final_state;
+ ),
+
+ TP_printk("%d: %s x %s -> %s %s",
+ __entry->id,
+ __entry->state,
+ __entry->event,
+ __entry->next_state,
+ __entry->final_state ? "(final)" : "")
+);
+
+DECLARE_EVENT_CLASS(error_da_monitor_id,
+
+ TP_PROTO(int id, char *state, char *event),
+
+ TP_ARGS(id, state, event),
+
+ TP_STRUCT__entry(
+ __field( int, id )
+ __array( char, state, MAX_DA_NAME_LEN )
+ __array( char, event, MAX_DA_NAME_LEN )
+ ),
+
+ TP_fast_assign(
+ memcpy(__entry->state, state, MAX_DA_NAME_LEN);
+ memcpy(__entry->event, event, MAX_DA_NAME_LEN);
+ __entry->id = id;
+ ),
+
+ TP_printk("%d: event %s not expected in the state %s",
+ __entry->id,
+ __entry->event,
+ __entry->state)
+);
+#endif /* CONFIG_DA_MON_EVENTS_ID */
+#endif /* _TRACE_RV_H */
+
+/* This part ust be outside protection */
+#undef TRACE_INCLUDE_PATH
+#include <trace/define_trace.h>
diff --git a/kernel/fork.c b/kernel/fork.c
index 9d44f2d46c69..6f1f82ccd5f2 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1964,6 +1964,18 @@ static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk)
mutex_unlock(&oom_adj_mutex);
}

+#ifdef CONFIG_RV
+static void rv_task_fork(struct task_struct *p)
+{
+ int i;
+
+ for (i = 0; i < RV_PER_TASK_MONITORS; i++)
+ p->rv[i].da_mon.monitoring = false;
+}
+#else
+#define rv_task_fork(p) do {} while (0)
+#endif
+
/*
* This creates a new process as a copy of the old one,
* but does not actually start it yet.
@@ -2399,6 +2411,8 @@ static __latent_entropy struct task_struct *copy_process(
*/
copy_seccomp(p);

+ rv_task_fork(p);
+
rseq_fork(p, clone_flags);

/* Don't start children in a dying pid namespace */
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 3eb5d48ab4f6..0123bdf7052a 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -1,5 +1,19 @@
# SPDX-License-Identifier: GPL-2.0-only
#
+config DA_MON_EVENTS
+ default n
+ bool
+
+config DA_MON_EVENTS_IMPLICIT
+ select DA_MON_EVENTS
+ default n
+ bool
+
+config DA_MON_EVENTS_ID
+ select DA_MON_EVENTS
+ default n
+ bool
+
menuconfig RV
bool "Runtime Verification"
depends on TRACING
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
index d988e2b1b9d2..00f1ffc49a7b 100644
--- a/kernel/trace/rv/rv.c
+++ b/kernel/trace/rv/rv.c
@@ -141,6 +141,11 @@
#include <linux/slab.h>
#include <rv/rv.h>

+#ifdef CONFIG_DA_MON_EVENTS
+#define CREATE_TRACE_POINTS
+#include <trace/events/rv.h>
+#endif
+
#include "rv.h"

DEFINE_MUTEX(rv_interface_lock);
--
2.35.1

Subject: [PATCH V5 15/16] rv/reactor: Add the printk reactor

A reactor that printks the reaction message.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
kernel/trace/rv/Kconfig | 8 ++++++
kernel/trace/rv/Makefile | 3 ++-
kernel/trace/rv/reactor_printk.c | 42 ++++++++++++++++++++++++++++++++
3 files changed, 52 insertions(+), 1 deletion(-)
create mode 100644 kernel/trace/rv/reactor_printk.c

diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index d8c40fd67e88..f1d92d431130 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -63,3 +63,11 @@ config RV_REACTORS
on the model's execution. By default, the monitors have
tracing reactions, printing the monitor output via tracepoints,
but other reactions can be added (on-demand) via this interface.
+
+config RV_REACT_PRINTK
+ bool "Printk reactor"
+ depends on RV_REACTORS
+ default y
+ help
+ Enables the printk reactor. The printk reactor emits a printk()
+ message if an exception is found.
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index af0ff9a46418..a13c750a35c1 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0

obj-$(CONFIG_RV) += rv.o
-obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
obj-$(CONFIG_RV_MON_WIP) += monitors/wip/wip.o
obj-$(CONFIG_RV_MON_WWNR) += monitors/wwnr/wwnr.o
+obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
+obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
diff --git a/kernel/trace/rv/reactor_printk.c b/kernel/trace/rv/reactor_printk.c
new file mode 100644
index 000000000000..aca11a818966
--- /dev/null
+++ b/kernel/trace/rv/reactor_printk.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+ *
+ * Printk RV reactor:
+ * Prints the exception msg to the kernel message log.
+ */
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+
+static void rv_printk_reaction(char *msg)
+{
+ printk_deferred(msg);
+}
+
+struct rv_reactor rv_printk = {
+ .name = "printk",
+ .description = "prints the exception msg to the kernel message log",
+ .react = rv_printk_reaction
+};
+
+int register_react_printk(void)
+{
+ rv_register_reactor(&rv_printk);
+ return 0;
+}
+
+void unregister_react_printk(void)
+{
+ rv_unregister_reactor(&rv_printk);
+}
+
+module_init(register_react_printk);
+module_exit(unregister_react_printk);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira");
+MODULE_DESCRIPTION("printk rv reactor: printk if an exception is hit");
--
2.35.1

Subject: [PATCH V5 10/16] Documentation/rv: Add deterministic automata monitor synthesis documentation

Add the da_monitor_synthesis.rst introduces some concepts behind the
Deterministic Automata (DA) monitor synthesis and interface.

Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Gabriele Paoloni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Tao Zhou <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
.../trace/rv/da_monitor_synthesis.rst | 147 ++++++++++++++++++
Documentation/trace/rv/index.rst | 1 +
include/rv/da_monitor.h | 3 +
tools/verification/dot2/dot2k | 3 +
tools/verification/dot2/dot2k.py | 3 +
5 files changed, 157 insertions(+)
create mode 100644 Documentation/trace/rv/da_monitor_synthesis.rst

diff --git a/Documentation/trace/rv/da_monitor_synthesis.rst b/Documentation/trace/rv/da_monitor_synthesis.rst
new file mode 100644
index 000000000000..427ed4f4729b
--- /dev/null
+++ b/Documentation/trace/rv/da_monitor_synthesis.rst
@@ -0,0 +1,147 @@
+Deterministic Automata Monitor Synthesis
+========================================
+
+The starting point for the application of runtime verification (RV) technics
+is the *specification* or *modeling* of the desired (or undesired) behavior
+of the system under scrutiny.
+
+The formal representation needs to be then *synthesized* into a *monitor*
+that can then be used in the analysis of the trace of the system. The
+*monitor* connects to the system via an *instrumentation* that converts
+the events from the *system* to the events of the *specification*.
+
+
+In Linux terms, the runtime verification monitors are encapsulated inside
+the *RV monitor* abstraction. The RV monitor includes a set of instances
+of the monitor (per-cpu monitor, per-task monitor, and so on), the helper
+functions that glue the monitor to the system reference model, and the
+trace output as a reaction to event parsing and exceptions, as depicted
+below::
+
+ Linux +----- RV Monitor ----------------------------------+ Formal
+ Realm | | Realm
+ +-------------------+ +----------------+ +-----------------+
+ | Linux kernel | | Monitor | | Reference |
+ | Tracing | -> | Instance(s) | <- | Model |
+ | (instrumentation) | | (verification) | | (specification) |
+ +-------------------+ +----------------+ +-----------------+
+ | | |
+ | V |
+ | +----------+ |
+ | | Reaction | |
+ | +--+--+--+-+ |
+ | | | | |
+ | | | +-> trace output ? |
+ +------------------------|--|----------------------+
+ | +----> panic ?
+ +-------> <user-specified>
+
+DA monitor synthesis
+--------------------
+
+The synthesis of automata-based models into the Linux *RV monitor* abstraction
+is automated by the dot2k tool and the rv/da_monitor.h header file that
+contains a set of macros that automatically generate the monitor's code.
+
+dot2k
+-----
+
+The dot2k utility leverages dot2c by converting an automaton model in
+the DOT format into the C representation [1] and creating the skeleton of
+a kernel monitor in C.
+
+For example, it is possible to transform the wip.dot model present in
+[1] into a per-cpu monitor with the following command::
+
+ $ dot2k -d wip.dot -t per_cpu
+
+This will create a directory named wip/ with the following files:
+
+- wip.h: the wip model in C
+- wip.c: the RV monitor
+
+The wip.c file contains the monitor declaration and the starting point for
+the system instrumentation.
+
+Monitor macros
+--------------
+
+The rv/da_monitor.h enables automatic code generation for the *Monitor
+Instance(s)* using C macros.
+
+The benefits of the usage of macro for monitor synthesis are 3-fold as it:
+
+- Reduces the code duplication;
+- Facilitates the bug fix/improvement;
+- Avoids the case of developers changing the core of the monitor code
+ to manipulate the model in a (let's say) non-standard way.
+
+This initial implementation presents three different types of monitor instances:
+
+- ``#define DECLARE_DA_MON_GLOBAL(name, type)``
+- ``#define DECLARE_DA_MON_PER_CPU(name, type)``
+- ``#define DECLARE_DA_MON_PER_TASK(name, type)``
+
+The first declares the functions for a global deterministic automata monitor,
+the second for monitors with per-cpu instances, and the third with per-task
+instances.
+
+In all cases, the 'name' argument is a string that identifies the monitor, and
+the 'type' argument is the data type used by dot2k on the representation of
+the model in C.
+
+For example, the wip model with two states and three events can be
+stored in an 'unsigned char' type. Considering that the preemption control
+is a per-cpu behavior, the monitor declaration in the 'wip.c' file is::
+
+ DECLARE_DA_MON_PER_CPU(wip, unsigned char);
+
+The monitor is executed by sending events to be processed via the functions
+presented below::
+
+ da_handle_event_$(MONITOR_NAME)($(event from event enum));
+ da_handle_init_event_$(MONITOR_NAME)($(event from event enum));
+ da_handle_init_run_event_$(MONITOR_NAME)($(event from event enum));
+
+The function ``da_handle_event_$(MONITOR_NAME)()`` is the regular case where
+the event will be processed if the monitor is processing events.
+
+When a monitor is enabled, it is placed in the initial state of the automata.
+However, the monitor does not know if the system is in the *initial state*.
+
+The ``da_handle_init_event_$(MONITOR_NAME)()`` function is used to notify the
+monitor that the system is returning to the initial state, so the monitor can
+start monitoring the next event.
+
+The ``da_handle_init_run_event_$(MONITOR_NAME)()`` function is used to notify
+the monitor that the system is known to be in the initial state, so the
+monitor can start monitoring and monitor the current event.
+
+Using the wip model as example, the events "preempt_disable" and
+"sched_waking" should be sent to monitor, respectively, via [2]::
+
+ da_handle_event_wip(preempt_disable_wip);
+ da_handle_event_wip(sched_waking_wip);
+
+While the event "preempt_enabled" will use::
+
+ da_handle_init_event_wip(preempt_enable_wip);
+
+To notify the monitor that the system will be returning to the initial state,
+so the system and the monitor should be in sync.
+
+Final remarks
+-------------
+
+With the monitor synthesis in place using the rv/da_monitor.h and
+dot2k, the developer's work should be limited to the instrumentation
+of the system, increasing the confidence in the overall approach.
+
+[1] For details about deterministic automata format and the translation
+from one representation to another, see::
+
+ Documentation/trace/rv/deterministic_automata.rst
+
+[2] dot2k appends the monitor's name suffix to the events enums to
+avoid conflicting variables when exporting the global vmlinux.h
+use by BPF programs.
diff --git a/Documentation/trace/rv/index.rst b/Documentation/trace/rv/index.rst
index 013a41a410cf..46d47f33052c 100644
--- a/Documentation/trace/rv/index.rst
+++ b/Documentation/trace/rv/index.rst
@@ -8,3 +8,4 @@ Runtime Verification

runtime-verification.rst
deterministic_automata.rst
+ da_monitor_synthesis.rst
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index d21045e6c5fc..7a1e6fcd642e 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -6,6 +6,9 @@
* with automata models in C generated by the dot2k tool.
*
* The dot2k tool is available at tools/verification/dot2k/
+ *
+ * For further information, see:
+ * Documentation/trace/rv/da_monitor_synthesis.rst
*/

#include <rv/automata.h>
diff --git a/tools/verification/dot2/dot2k b/tools/verification/dot2/dot2k
index 69106f4b7682..9dcd38abe20a 100644
--- a/tools/verification/dot2/dot2k
+++ b/tools/verification/dot2/dot2k
@@ -4,6 +4,9 @@
# Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
#
# dot2k: transform dot files into a monitor for the Linux kernel.
+#
+# For further information, see:
+# Documentation/trace/rv/da_monitor_synthesis.rst

if __name__ == '__main__':
from dot2.dot2k import dot2k
diff --git a/tools/verification/dot2/dot2k.py b/tools/verification/dot2/dot2k.py
index 4eecd69c2568..2856e1ce1259 100644
--- a/tools/verification/dot2/dot2k.py
+++ b/tools/verification/dot2/dot2k.py
@@ -4,6 +4,9 @@
# Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
#
# dot2k: transform dot files into a monitor for the Linux kernel.
+#
+# For further information, see:
+# Documentation/trace/rv/da_monitor_synthesis.rst

from dot2.dot2c import Dot2c
import platform
--
2.35.1

2022-07-17 15:23:09

by Tao Zhou

[permalink] [raw]
Subject: Re: [PATCH V5 06/16] Documentation/rv: Add a basic documentation

On Wed, Jul 13, 2022 at 11:17:22PM +0200, Daniel Bristot de Oliveira wrote:
> Add the runtime-verification.rst document, explaining the basics of RV
> and how to use the interface.
>
> Cc: Wim Van Sebroeck <[email protected]>
> Cc: Guenter Roeck <[email protected]>
> Cc: Jonathan Corbet <[email protected]>
> Cc: Steven Rostedt <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: Marco Elver <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: Shuah Khan <[email protected]>
> Cc: Gabriele Paoloni <[email protected]>
> Cc: Juri Lelli <[email protected]>
> Cc: Clark Williams <[email protected]>
> Cc: Tao Zhou <[email protected]>
> Cc: Randy Dunlap <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
> ---
> Documentation/trace/index.rst | 1 +
> Documentation/trace/rv/index.rst | 9 +
> .../trace/rv/runtime-verification.rst | 233 ++++++++++++++++++
> kernel/trace/rv/Kconfig | 3 +
> kernel/trace/rv/rv.c | 3 +
> 5 files changed, 249 insertions(+)
> create mode 100644 Documentation/trace/rv/index.rst
> create mode 100644 Documentation/trace/rv/runtime-verification.rst
> + runtime-verification.rst

[snip]

> +The user interface
> +==================
> +
> +The user interface resembles the tracing interface (on purpose). It is
> +currently at "/sys/kernel/tracing/rv/".
> +
> +The following files/folders are currently available:
> +
> +**available_monitors**
> +
> +- Reading list the available monitors, one per line
> +
> +For example::
> +
> + # cat available_monitors
> + wip
> + wwnr
> +
> +**available_reactors**
> +
> +- Reading shows the available reactors, one per line.
> +
> +For example::
> +
> + # cat available_reactors
> + nop
> + panic
> + printk
> +
> +**enabled_monitors**:
> +
> +- Reading lists the enabled monitors, one per line
> +- Writing to it enables a given monitor
> +- Writing a monitor name with a '-' prefix disables it

s/-/!/

> +- Truncating the file disables all enabled monitors
> +
> +For example::
> +
> + # cat enabled_monitors
> + # echo wip > enabled_monitors
> + # echo wwnr >> enabled_monitors
> + # cat enabled_monitors
> + wip
> + wwnr
> + # echo '!wip' >> enabled_monitors
> + # cat enabled_monitors
> + wwnr
> + # echo > enabled_monitors
> + # cat enabled_monitors
> + #
> +
> +Note that it is possible to enable more than one monitor concurrently.
> +
> +
> +**monitoring_on**
> +
> +This is an on/off general switcher for monitoring. It resembles the
> +"tracing_on" switcher in the trace interface.
> +
> +- Writing "0" stops the monitoring
> +- Writing "1" continues the monitoring
> +- Reading returns the current status of the monitoring
> +
> +Note that it does not disable enabled monitors but stop the per-entity
> +monitors monitoring the events received from the system.
> +
> +**reacting_on**
> +
> +- Writing "0" prevents reactions for happening
> +- Writing "1" enable reactions
> +- Reading returns the current status of the monitoring

s/monitoring/reaction/

2022-07-17 15:25:13

by Tao Zhou

[permalink] [raw]
Subject: Re: [PATCH V5 11/16] Documentation/rv: Add deterministic automata instrumentation documentation

On Wed, Jul 13, 2022 at 11:17:27PM +0200, Daniel Bristot de Oliveira wrote:
> Add the da_monitor_instrumentation.rst. It describes the basics
> of RV monitor instrumentation.
>
> Cc: Wim Van Sebroeck <[email protected]>
> Cc: Guenter Roeck <[email protected]>
> Cc: Jonathan Corbet <[email protected]>
> Cc: Steven Rostedt <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: Marco Elver <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: Shuah Khan <[email protected]>
> Cc: Gabriele Paoloni <[email protected]>
> Cc: Juri Lelli <[email protected]>
> Cc: Clark Williams <[email protected]>
> Cc: Tao Zhou <[email protected]>
> Cc: Randy Dunlap <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
> ---
> .../trace/rv/da_monitor_instrumentation.rst | 169 ++++++++++++++++++
> Documentation/trace/rv/index.rst | 1 +
> 2 files changed, 170 insertions(+)
> create mode 100644 Documentation/trace/rv/da_monitor_instrumentation.rst
>
> diff --git a/Documentation/trace/rv/da_monitor_instrumentation.rst b/Documentation/trace/rv/da_monitor_instrumentation.rst
> new file mode 100644
> index 000000000000..7b83d6c7dbed
> --- /dev/null
> +++ b/Documentation/trace/rv/da_monitor_instrumentation.rst
> @@ -0,0 +1,169 @@
> +Deterministic Automata Instrumentation
> +========================================
> +
> +The RV monitor file created by dot2k, with the name "$MODEL_NAME.c"
> +includes a section dedicated to instrumentation.
> +
> +In the example of the wip.dot monitor created on [1], it will look like::
> +
> + /*
> + * This is the instrumentation part of the monitor.
> + *
> + * This is the section where manual work is required. Here the kernel events
> + * are translated into model's event.
> + *
> + */
> + static void handle_preempt_disable(void *data, /* XXX: fill header */)
> + {
> + da_handle_event_wip(preempt_disable_wip);
> + }
> +
> + static void handle_preempt_enable(void *data, /* XXX: fill header */)
> + {
> + da_handle_event_wip(preempt_enable_wip);
> + }
> +
> + static void handle_sched_waking(void *data, /* XXX: fill header */)
> + {
> + da_handle_event_wip(sched_waking_wip);
> + }
> +
> + static int start_wip(void)
> + {
> + int retval;
> +
> + retval = da_monitor_init_wip();
> + if (retval)
> + return retval;
> +
> + rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_disable);
> + rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_preempt_enable);
> + rv_attach_trace_probe("wip", /* XXX: tracepoint */, handle_sched_waking);
> +
> + return 0;
> + }
> +
> +The comment at the top of the section explains the general idea: the
> +instrumentation section translates *kernel events* into the *model's
> +event*.
> +
> +Tracing callback functions
> +-----------------------------
> +
> +The first three functions are the starting point of the callback *handler
> +functions* for each of the three events from the wip model. The developer
> +does not necessarily need to use them: they are just starting points.
> +
> +Using the example of::
> +
> + void handle_preempt_disable(void *data, /* XXX: fill header */)
> + {
> + da_handle_event_wip(preempt_disable_wip);
> + }
> +
> +The preempt_disable event from the model connects directly to the
> +preemptirq:preempt_disable. The preemptirq:preempt_disable event
> +has the following signature, from include/trace/events/preemptirq.h::
> +
> + TP_PROTO(unsigned long ip, unsigned long parent_ip)
> +
> +Hence, the handle_preempt_disable() function will look like::
> +
> + void handle_preempt_disable(void *data, unsigned long ip, unsigned long parent_ip)
> +
> +In this case, the kernel event translates one to one with the automata
> +event, and indeed, no other change is required for this function.
> +
> +The next handler function, handle_preempt_enable() has the same argument
> +list from the handle_preempt_disable(). The difference is that the
> +preempt_enable event will be used to synchronize the system to the model.
> +
> +Initially, the *model* is placed in the initial state. However, the *system*
> +might or might not be in the initial state. The monitor cannot start
> +processing events until it knows that the system has reached the initial state.
> +Otherwise, the monitor and the system could be out-of-sync.
> +
> +Looking at the automata definition, it is possible to see that the system
> +and the model are expected to return to the initial state after the
> +preempt_enable execution. Hence, it can be used to synchronize the
> +system and the model at the initialization of the monitoring section.
> +
> +The initialization is informed via a special handle function, the
> +"da_handle_init_event_$(MONITOR)(event)", in this case::
> +
> + da_handle_event_wip(preempt_disable_wip);

In this case, it is da_handle_init_event_wip(preempt_disable_wip). Thanks.

2022-07-17 15:42:28

by Tao Zhou

[permalink] [raw]
Subject: Re: [PATCH V5 04/16] rv/include: Add deterministic automata monitor definition via C macros

On Wed, Jul 13, 2022 at 11:17:20PM +0200, Daniel Bristot de Oliveira wrote:
> In Linux terms, the runtime verification monitors are encapsulated
> inside the "RV monitor" abstraction. The "RV monitor" includes a set
> of instances of the monitor (per-cpu monitor, per-task monitor, and
> so on), the helper functions that glue the monitor to the system
> reference model, and the trace output as a reaction for event parsing
> and exceptions, as depicted below:
>
> Linux +----- RV Monitor ----------------------------------+ Formal
> Realm | | Realm
> +-------------------+ +----------------+ +-----------------+
> | Linux kernel | | Monitor | | Reference |
> | Tracing | -> | Instance(s) | <- | Model |
> | (instrumentation) | | (verification) | | (specification) |
> +-------------------+ +----------------+ +-----------------+
> | | |
> | V |
> | +----------+ |
> | | Reaction | |
> | +--+--+--+-+ |
> | | | | |
> | | | +-> trace output ? |
> +------------------------|--|----------------------+
> | +----> panic ?
> +-------> <user-specified>
>
> Add the rv/da_monitor.h, enabling automatic code generation for the
> *Monitor Instance(s)* using C macros, and code to support it.
>
> The benefits of the usage of macro for monitor synthesis are 3-fold as it:
>
> - Reduces the code duplication;
> - Facilitates the bug fix/improvement;
> - Avoids the case of developers changing the core of the monitor code
> to manipulate the model in a (let's say) non-standard way.
>
> This initial implementation presents three different types of monitor
> instances:
>
> - DECLARE_DA_MON_GLOBAL(name, type)
> - DECLARE_DA_MON_PER_CPU(name, type)
> - DECLARE_DA_MON_PER_TASK(name, type)
>
> The first declares the functions for a global deterministic automata monitor,
> the second for monitors with per-cpu instances, and the third with per-task
> instances.
>
> Cc: Wim Van Sebroeck <[email protected]>
> Cc: Guenter Roeck <[email protected]>
> Cc: Jonathan Corbet <[email protected]>
> Cc: Steven Rostedt <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: Marco Elver <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: Shuah Khan <[email protected]>
> Cc: Gabriele Paoloni <[email protected]>
> Cc: Juri Lelli <[email protected]>
> Cc: Clark Williams <[email protected]>
> Cc: Tao Zhou <[email protected]>
> Cc: Randy Dunlap <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
> ---
> include/linux/rv.h | 2 +
> include/rv/da_monitor.h | 521 ++++++++++++++++++++++++++++++++++++++
> include/rv/rv.h | 9 +
> include/trace/events/rv.h | 120 +++++++++
> kernel/fork.c | 14 +
> kernel/trace/rv/Kconfig | 14 +
> kernel/trace/rv/rv.c | 5 +
> 7 files changed, 685 insertions(+)
> create mode 100644 include/rv/da_monitor.h
> create mode 100644 include/trace/events/rv.h
>
> diff --git a/include/linux/rv.h b/include/linux/rv.h
> index 88d28d207f3a..bdefdff12a1f 100644
> --- a/include/linux/rv.h
> +++ b/include/linux/rv.h
> @@ -7,6 +7,8 @@
> #ifndef _LINUX_RV_H
> #define _LINUX_RV_H
>
> +#define MAX_DA_NAME_LEN 24
> +
> struct rv_reactor {
> char *name;
> char *description;
> diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
> new file mode 100644
> index 000000000000..d21045e6c5fc
> --- /dev/null
> +++ b/include/rv/da_monitor.h
> @@ -0,0 +1,521 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
> + *
> + * Deterministic automata (DA) monitor functions, to be used together
> + * with automata models in C generated by the dot2k tool.
> + *
> + * The dot2k tool is available at tools/verification/dot2k/
> + */
> +
> +#include <rv/automata.h>
> +#include <linux/rv.h>
> +
> +/*
> + * Generic helpers for all types of deterministic automata monitors.
> + */
> +#define DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
> +static char REACT_MSG[1024]; \
> + \
> +static inline char *format_react_msg(type curr_state, type event) \
> +{ \
> + snprintf(REACT_MSG, 1024, \
> + "rv: monitor %s does not allow event %s on state %s\n", \
> + #name, \
> + model_get_event_name_##name(event), \
> + model_get_state_name_##name(curr_state)); \
> + return REACT_MSG; \
> +} \
> + \
> +static void cond_react(char *msg) \
> +{ \
> + if (rv_##name.react) \
> + rv_##name.react(msg); \
> +} \
> + \
> +/* \
> + * da_monitor_reset_##name - reset a monitor and setting it to init state \
> + */ \
> +static inline void da_monitor_reset_##name(struct da_monitor *da_mon) \
> +{ \
> + da_mon->monitoring = 0; \
> + da_mon->curr_state = model_get_init_state_##name(); \
> +} \
> + \
> +/* \
> + * da_monitor_curr_state_##name - return the current state \
> + */ \
> +static inline type da_monitor_curr_state_##name(struct da_monitor *da_mon) \
> +{ \
> + return da_mon->curr_state; \
> +} \
> + \
> +/* \
> + * da_monitor_set_state_##name - set the new current state \
> + */ \
> +static inline void \
> +da_monitor_set_state_##name(struct da_monitor *da_mon, enum states_##name state)\
> +{ \
> + da_mon->curr_state = state; \
> +} \
> + \
> +/* \
> + * da_monitor_start_##name - start monitoring \
> + * \
> + * The monitor will ignore all events until monitoring is set to true. This \
> + * function needs to be called to tell the monitor to start monitoring. \
> + */ \
> +static inline void da_monitor_start_##name(struct da_monitor *da_mon) \
> +{ \
> + da_mon->monitoring = 1; \
> +} \
> + \
> +/* \
> + * da_monitoring_##name - returns true if the monitor is processing events \
> + */ \
> +static inline bool da_monitoring_##name(struct da_monitor *da_mon) \
> +{ \
> + return da_mon->monitoring; \
> +}
> +
> +
> +/*
> + * Event handler for implicit monitors. Implicit monitor is the one which the
> + * handler does not need to specify which da_monitor to manipulate. Examples
> + * of implicit monitor are the per_cpu or the global ones.
> + */
> +#define DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
> +static inline bool \
> +da_event_##name(struct da_monitor *da_mon, enum events_##name event) \
> +{ \
> + type curr_state = da_monitor_curr_state_##name(da_mon); \
> + type next_state = model_get_next_state_##name(curr_state, event); \
> + \
> + if (next_state != INVALID_STATE) { \
> + da_monitor_set_state_##name(da_mon, next_state); \
> + \
> + trace_event_##name(model_get_state_name_##name(curr_state), \
> + model_get_event_name_##name(event), \
> + model_get_state_name_##name(next_state), \
> + model_is_final_state_##name(next_state)); \
> + \
> + return true; \
> + } \
> + \
> + if (reacting_on) \
> + cond_react(format_react_msg(curr_state, event)); \
> + \
> + trace_error_##name(model_get_state_name_##name(curr_state), \
> + model_get_event_name_##name(event)); \
> + \
> + return false; \
> +} \
> +
> +/*
> + * Event handler for per_task monitors.
> + */
> +#define DECLARE_DA_MON_MODEL_HANDLER_PER_TASK(name, type) \
> +static inline type \
> +da_event_##name(struct da_monitor *da_mon, struct task_struct *tsk, \
> + enum events_##name event) \
> +{ \
> + type curr_state = da_monitor_curr_state_##name(da_mon); \
> + type next_state = model_get_next_state_##name(curr_state, event); \
> + \
> + if (next_state != INVALID_STATE) { \
> + da_monitor_set_state_##name(da_mon, next_state); \
> + \
> + trace_event_##name(tsk->pid, \
> + model_get_state_name_##name(curr_state), \
> + model_get_event_name_##name(event), \
> + model_get_state_name_##name(next_state), \
> + model_is_final_state_##name(next_state)); \
> + \
> + return true; \
> + } \
> + \
> + if (reacting_on) \
> + cond_react(format_react_msg(curr_state, event)); \
> + \
> + trace_error_##name(tsk->pid, \
> + model_get_state_name_##name(curr_state), \
> + model_get_event_name_##name(event)); \
> + \
> + return false; \
> +}
> +
> +/*
> + * Functions to define, init and get a global monitor.
> + */
> +#define DECLARE_DA_MON_INIT_GLOBAL(name, type) \
> + \
> +/* \
> + * global monitor (a single variable) \
> + */ \
> +static struct da_monitor da_mon_##name; \
> + \
> +/* \
> + * da_get_monitor_##name - return the global monitor address \
> + */ \
> +static struct da_monitor *da_get_monitor_##name(void) \
> +{ \
> + return &da_mon_##name; \
> +} \
> + \
> +/* \
> + * da_monitor_reset_all_##name - reset the single monitor \
> + */ \
> +static void da_monitor_reset_all_##name(void) \
> +{ \
> + da_monitor_reset_##name(&da_mon_##name); \
> +} \
> + \
> +/* \
> + * da_monitor_init_##name - initialize a monitor \
> + */ \
> +static inline int da_monitor_init_##name(void) \
> +{ \
> + struct da_monitor *da_mon = &da_mon_##name; \
> + da_mon->curr_state = model_get_init_state_##name(); \
> + da_mon->monitoring = 0; \
> + return 0; \
> +} \
> + \
> +/* \
> + * da_monitor_destroy_##name - destroy the monitor \
> + */ \
> +static inline void da_monitor_destroy_##name(void) \
> +{ \
> + return; \
> +}
> +
> +/*
> + * Functions to define, init and get a per-cpu monitor.
> + */
> +#define DECLARE_DA_MON_INIT_PER_CPU(name, type) \
> + \
> +/* \
> + * per-cpu monitor variables \
> + */ \
> +DEFINE_PER_CPU(struct da_monitor, da_mon_##name); \
> + \
> +/* \
> + * da_get_monitor_##name - return current CPU monitor address \
> + */ \
> +static struct da_monitor *da_get_monitor_##name(void) \
> +{ \
> + return this_cpu_ptr(&da_mon_##name); \
> +} \
> + \
> +/* \
> + * da_monitor_reset_all_##name - reset all CPUs' monitor \
> + */ \
> +static void da_monitor_reset_all_##name(void) \
> +{ \
> + struct da_monitor *da_mon; \
> + int cpu; \
> + for_each_cpu(cpu, cpu_online_mask) { \
> + da_mon = per_cpu_ptr(&da_mon_##name, cpu); \
> + da_monitor_reset_##name(da_mon); \
> + } \
> +} \
> + \
> +/* \
> + * da_monitor_init_##name - initialize all CPUs' monitor \
> + */ \
> +static inline int da_monitor_init_##name(void) \
> +{ \
> + struct da_monitor *da_mon; \
> + int cpu; \
> + for_each_cpu(cpu, cpu_online_mask) { \
> + da_mon = per_cpu_ptr(&da_mon_##name, cpu); \
> + da_mon->curr_state = model_get_init_state_##name(); \
> + da_mon->monitoring = 0; \
> + } \
> + return 0; \
> +} \
> + \
> +/* \
> + * da_monitor_destroy_##name - destroy the monitor \
> + */ \
> +static inline void da_monitor_destroy_##name(void) \
> +{ \
> + return; \
> +}
> +
> +/*
> + * Functions to define, init and get a per-task monitor.
> + */
> +#define DECLARE_DA_MON_INIT_PER_TASK(name, type) \
> + \
> +/* \
> + * The per-task monitor is stored a vector in the task struct. This variable \
> + * stores the position on the vector reserved for this monitor. \
> + */ \
> +static int task_mon_slot_##name = RV_PER_TASK_MONITOR_INIT; \

In patch1, RV_PER_TASK_MONITOR_INIT is defined as:

#define RV_PER_TASK_MONITORS 1
#define RV_PER_TASK_MONITOR_INIT (RV_PER_TASK_MONITORS)

RV_PER_TASK_MONITOR_INIT is 1 now, seems not the index of the first only
element in vector. Now no map here, one task has one monitor though if I
am not wrong.
So task_mon_slot_##name must be defined to the index of first element.
Modify the macro definition of RV_PER_TASK_MONITOR_INIT to the index of
first element in vector.

#define RV_PER_TASK_MONITOR_INIT (RV_PER_TASK_MONITORS) - 1

If there are more monitors per task in the furture, like you say, dynamic
allocation and mapping should be used. But I don't know.

2022-07-17 15:43:13

by Tao Zhou

[permalink] [raw]
Subject: Re: [PATCH V5 02/16] rv: Add runtime reactors interface

On Wed, Jul 13, 2022 at 11:17:18PM +0200, Daniel Bristot de Oliveira wrote:
> A runtime monitor can cause a reaction to the detection of an
> exception on the model's execution. By default, the monitors have
> tracing reactions, printing the monitor output via tracepoints.
> But other reactions can be added (on-demand) via this interface.
>
> The user interface resembles the kernel tracing interface and
> presents these files:
>
> "available_reactors"
> - Reading shows the available reactors, one per line.
>
> For example:
> # cat available_reactors
> nop
> panic
> printk
>
> "reacting_on"
> - It is an on/off general switch for reactors, disabling
> all reactions.
>
> "monitors/MONITOR/reactors"
> - List available reactors, with the select reaction for the given
> MONITOR inside []. The default one is the nop (no operation)
> reactor.
> - Writing the name of a reactor enables it to the given
> MONITOR.
>
> For example:
> # cat monitors/wip/reactors
> [nop]
> panic
> printk
> # echo panic > monitors/wip/reactors
> # cat monitors/wip/reactors
> nop
> [panic]
> printk
>
> Cc: Wim Van Sebroeck <[email protected]>
> Cc: Guenter Roeck <[email protected]>
> Cc: Jonathan Corbet <[email protected]>
> Cc: Steven Rostedt <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: Marco Elver <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: Shuah Khan <[email protected]>
> Cc: Gabriele Paoloni <[email protected]>
> Cc: Juri Lelli <[email protected]>
> Cc: Clark Williams <[email protected]>
> Cc: Tao Zhou <[email protected]>
> Cc: Randy Dunlap <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
> ---
> include/linux/rv.h | 11 +
> kernel/trace/rv/Kconfig | 11 +
> kernel/trace/rv/Makefile | 1 +
> kernel/trace/rv/rv.c | 9 +
> kernel/trace/rv/rv.h | 29 ++
> kernel/trace/rv/rv_reactors.c | 488 ++++++++++++++++++++++++++++++++++
> 6 files changed, 549 insertions(+)
> create mode 100644 kernel/trace/rv/rv_reactors.c

[snip]

> new file mode 100644
> index 000000000000..27f48fec5a51
> --- /dev/null
> +++ b/kernel/trace/rv/rv_reactors.c
> @@ -0,0 +1,488 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
> + *
> + * Runtime reactor interface.
> + *
> + * A runtime monitor can cause a reaction to the detection of an
> + * exception on the model's execution. By default, the monitors have
> + * tracing reactions, printing the monitor output via tracepoints.
> + * But other reactions can be added (on-demand) via this interface.
> + *
> + * == Registering reactors ==
> + *
> + * The struct rv_reactor defines a callback function to be executed
> + * in case of a model exception happens. The callback function
> + * receives a message to be (optionally) printed before executing
> + * the reaction.
> + *
> + * A RV reactor is registered via:
> + * int rv_register_reactor(struct rv_reactor *reactor)
> + * And unregistered via:
> + * int rv_unregister_reactor(struct rv_reactor *reactor)
> + *
> + * These functions are exported to modules, enabling reactors to be
> + * dynamically loaded.
> + *
> + * == User interface ==
> + *
> + * The user interface resembles the kernel tracing interface and
> + * presents these files:
> + *
> + * "available_reactors"
> + * - List the available reactors, one per line.
> + *
> + * For example:
> + * # cat available_reactors
> + * nop
> + * panic
> + * printk
> + *
> + * "reacting_on"
> + * - It is an on/off general switch for reactors, disabling
> + * all reactions.
> + *
> + * "monitors/MONITOR/reactors"
> + * - List available reactors, with the select reaction for the given
> + * MONITOR inside []. The default one is the nop (no operation)
> + * reactor.
> + * - Writing the name of an reactor enables it to the given
> + * MONITOR.
> + *
> + * For example:
> + * # cat monitors/wip/reactors
> + * [nop]
> + * panic
> + * printk
> + * # echo panic > monitors/wip/reactors
> + * # cat monitors/wip/reactors
> + * nop
> + * [panic]
> + * printk
> + */
> +
> +#include <linux/slab.h>
> +
> +#include "rv.h"
> +
> +bool __read_mostly reacting_on;
> +
> +/*
> + * Interface for the reactor register.
> + */
> +LIST_HEAD(rv_reactors_list);
> +
> +static struct rv_reactor_def *get_reactor_rdef_by_name(char *name)
> +{
> + struct rv_reactor_def *r;
> +
> + list_for_each_entry(r, &rv_reactors_list, list) {
> + if (strcmp(name, r->reactor->name) == 0)
> + return r;
> + }
> + return NULL;
> +}
> +
> +/*
> + * Available reactors seq functions.
> + */
> +static int reactors_show(struct seq_file *m, void *p)
> +{
> + struct rv_reactor_def *rea_def = p;
> +
> + seq_printf(m, "%s\n", rea_def->reactor->name);
> + return 0;
> +}
> +
> +static void reactors_stop(struct seq_file *m, void *p)
> +{
> + mutex_unlock(&rv_interface_lock);
> +}
> +
> +static void *reactors_start(struct seq_file *m, loff_t *pos)
> +{
> + mutex_lock(&rv_interface_lock);
> + return seq_list_start(&rv_reactors_list, *pos);
> +}
> +
> +static void *reactors_next(struct seq_file *m, void *p, loff_t *pos)
> +{
> + return seq_list_next(p, &rv_reactors_list, pos);
> +}
> +
> +/*
> + * available reactors seq definition.
> + */
> +static const struct seq_operations available_reactors_seq_ops = {
> + .start = reactors_start,
> + .next = reactors_next,
> + .stop = reactors_stop,
> + .show = reactors_show
> +};
> +
> +/*
> + * available_reactors interface.
> + */
> +static int available_reactors_open(struct inode *inode, struct file *file)
> +{
> + return seq_open(file, &available_reactors_seq_ops);
> +};
> +
> +static const struct file_operations available_reactors_ops = {
> + .open = available_reactors_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = seq_release
> +};
> +
> +/*
> + * Monitor reactor file.
> + */
> +static int monitor_reactor_show(struct seq_file *m, void *p)
> +{
> + struct rv_monitor_def *mdef = m->private;
> + struct rv_reactor_def *rdef = p;
> +
> + if (mdef->rdef == rdef)
> + seq_printf(m, "[%s]\n", rdef->reactor->name);
> + else
> + seq_printf(m, "%s\n", rdef->reactor->name);
> + return 0;
> +}
> +
> +/*
> + * available reactors seq definition.
> + */
> +static const struct seq_operations monitor_reactors_seq_ops = {
> + .start = reactors_start,
> + .next = reactors_next,
> + .stop = reactors_stop,
> + .show = monitor_reactor_show
> +};
> +
> +static ssize_t
> +monitor_reactors_write(struct file *file, const char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
> + struct rv_monitor_def *mdef;
> + struct rv_reactor_def *rdef;
> + struct seq_file *seq_f;
> + int retval = -EINVAL;
> + bool enabled;
> + char *ptr;
> + int len;
> +
> + if (count < 1 || count > MAX_RV_REACTOR_NAME_SIZE + 2)
> + return -EINVAL;

The same case as patch1. The up bound check need to be changed.

> +
> + memset(buff, 0, sizeof(buff));
> +
> + retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf,
> + count);
> + if (!retval)
> + return -EFAULT;

If simple_write_to_buffer() is error(return value < 0), no return here.
If the return value is 0, no write has happened. For this case, the code
want to return -EFAULT.

> +
> + ptr = strim(buff);
> +
> + len = strlen(ptr);
> + if (!len)
> + return count;
> +
> + /*
> + * See monitor_reactors_open()
> + */
> + seq_f = file->private_data;
> + mdef = seq_f->private;
> +
> + mutex_lock(&rv_interface_lock);
> +
> + retval = -EINVAL;
> +
> + /*
> + * nop special case: disable reacting.
> + */
> + if (strcmp(ptr, "nop") == 0) {
> +
> + enabled = mdef->monitor->enabled;
> + if (enabled)
> + mdef->monitor->stop();
> +
> + mdef->rdef = get_reactor_rdef_by_name("nop");
> + mdef->reacting = false;
> + mdef->monitor->react = NULL;
> +
> + if (enabled) {
> + mdef->monitor->start();
> + mdef->monitor->enabled = 1;
> + }
> +
> + retval = count;
> + goto unlock;
> + }
> +
> + list_for_each_entry(rdef, &rv_reactors_list, list) {
> + if (strcmp(ptr, rdef->reactor->name) != 0)
> + continue;
> +
> + /*
> + * found!
> + */
> + enabled = mdef->monitor->enabled;
> + if (enabled)
> + mdef->monitor->stop();
> +
> + mdef->rdef = rdef;
> + mdef->reacting = true;
> + mdef->monitor->react = rdef->reactor->react;
> +
> + if (enabled) {
> + mdef->monitor->start();
> + mdef->monitor->enabled = 1;
> + }
> +
> + retval = count;
> + break;
> + }
> +
> +unlock:
> + mutex_unlock(&rv_interface_lock);
> +
> + return retval;
> +}
> +
> +/*
> + * available_reactors interface.
> + */
> +static int monitor_reactors_open(struct inode *inode, struct file *file)
> +{
> + /*
> + * create file "private" info is stored in the inode->i_private
> + */
> + struct rv_monitor_def *mdef = inode->i_private;
> + struct seq_file *seq_f;
> + int ret;
> +
> + ret = seq_open(file, &monitor_reactors_seq_ops);
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * seq_open stores the seq_file on the file->private data.
> + */
> + seq_f = file->private_data;
> +
> + /*
> + * Copy the create file "private" data to the seq_file
> + * private data.
> + */
> + seq_f->private = mdef;
> +
> + return 0;
> +};
> +
> +static const struct file_operations monitor_reactors_ops = {
> + .open = monitor_reactors_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = seq_release,
> + .write = monitor_reactors_write
> +};
> +
> +static int __rv_register_reactor(struct rv_reactor *reactor)
> +{
> + struct rv_reactor_def *r;
> +
> + list_for_each_entry(r, &rv_reactors_list, list) {
> + if (strcmp(reactor->name, r->reactor->name) == 0) {
> + pr_info("Reactor %s is already registered\n",
> + reactor->name);
> + return -EINVAL;
> + }
> + }
> +
> + r = kzalloc(sizeof(struct rv_reactor_def), GFP_KERNEL);
> + if (!r)
> + return -ENOMEM;
> +
> + r->reactor = reactor;
> + r->counter = 0;
> +
> + list_add_tail(&r->list, &rv_reactors_list);
> +
> + return 0;
> +}
> +
> +/**
> + * rv_register_reactor - register a rv reactor.
> + * @reactor: The rv_reactor to be registered.
> + *
> + * Returns 0 if successful, error otherwise.
> + */
> +int rv_register_reactor(struct rv_reactor *reactor)
> +{
> + int retval = 0;
> +
> + if (strlen(reactor->name) >= MAX_RV_REACTOR_NAME_SIZE) {
> + pr_info("Reactor %s has a name longer than %d\n",
> + reactor->name, MAX_RV_MONITOR_NAME_SIZE);
> + return -EINVAL;
> + }
> +
> + mutex_lock(&rv_interface_lock);
> + retval = __rv_register_reactor(reactor);
> + mutex_unlock(&rv_interface_lock);
> + return retval;
> +}
> +
> +/**
> + * rv_unregister_reactor - unregister a rv reactor.
> + * @reactor: The rv_reactor to be unregistered.
> + *
> + * Returns 0 if successful, error otherwise.
> + */
> +int rv_unregister_reactor(struct rv_reactor *reactor)
> +{
> + struct rv_reactor_def *ptr, *next;
> +
> + mutex_lock(&rv_interface_lock);
> +
> + list_for_each_entry_safe(ptr, next, &rv_reactors_list, list) {
> + if (strcmp(reactor->name, ptr->reactor->name) == 0) {
> +
> + if (!ptr->counter) {
> + list_del(&ptr->list);
> + } else {
> + printk(KERN_WARNING
> + "rv: the rv_reactor %s is in use by %d monitor(s)\n",
> + ptr->reactor->name, ptr->counter);
> + printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
> + ptr->reactor->name);
> + return -EBUSY;
> + }
> +
> + }
> + }
> +
> + mutex_unlock(&rv_interface_lock);
> + return 0;
> +}
> +
> +/*
> + * reacting_on interface.
> + */
> +static ssize_t reacting_on_read_data(struct file *filp,
> + char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + char *buff;
> +
> + mutex_lock(&rv_interface_lock);
> + buff = reacting_on ? "1\n" : "0\n";
> + mutex_unlock(&rv_interface_lock);
> +
> + return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
> +}
> +
> +static void turn_reacting_off(void)
> +{
> + reacting_on = false;
> +}
> +
> +static void turn_reacting_on(void)
> +{
> + reacting_on = true;
> +}
> +
> +static ssize_t
> +reacting_on_write_data(struct file *filp, const char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + int retval;
> + bool val;
> +
> + retval = kstrtobool_from_user(user_buf, count, &val);
> + if (retval)
> + return retval;
> +
> + mutex_lock(&rv_interface_lock);
> +
> + if (val)
> + turn_reacting_on();
> + else
> + turn_reacting_off();
> +
> + mutex_unlock(&rv_interface_lock);
> +
> + return count;
> +}
> +
> +static const struct file_operations reacting_on_fops = {
> + .open = simple_open,
> + .llseek = no_llseek,
> + .write = reacting_on_write_data,
> + .read = reacting_on_read_data,
> +};
> +
> +int reactor_create_monitor_files(struct rv_monitor_def *mdef)
> +{
> + struct dentry *tmp;
> +
> + tmp = rv_create_file("reactors", RV_MODE_WRITE, mdef->root_d, mdef, &monitor_reactors_ops);
> + if (!tmp)
> + return -ENOMEM;
> +
> + /*
> + * Configure as the rv_nop reactor.
> + */
> + mdef->rdef = get_reactor_rdef_by_name("nop");
> + mdef->reacting = false;

Not need `mdef->monitor->react = NULL;`. The monitor->react is
not set to others that means it is set to NULL, When initializing
the specific rv_monitor structure. Note to myself. Thanks.

> +
> + return 0;
> +}
> +
> +/*
> + * None reactor register
> + */
> +static void rv_nop_reaction(char *msg)
> +{
> +}
> +
> +struct rv_reactor rv_nop = {
> + .name = "nop",
> + .description = "no-operation reactor: do nothing.",
> + .react = rv_nop_reaction
> +};
> +
> +/*
> + * This section collects the rv/ root dir files and folders.
> + */
> +int init_rv_reactors(struct dentry *root_dir)
> +{
> + struct dentry *available, *reacting;
> + int retval;
> +
> + available = rv_create_file("available_reactors", RV_MODE_READ, root_dir, NULL,
> + &available_reactors_ops);
> + if (!available)
> + goto out_err;
> +
> + reacting = rv_create_file("reacting_on", RV_MODE_WRITE, root_dir, NULL, &reacting_on_fops);
> + if (!reacting)
> + goto rm_available;
> +
> + retval = __rv_register_reactor(&rv_nop);
> + if (retval)
> + goto rm_reacting;
> +
> + reacting_on = 1;
> +
> + return 0;
> +
> +rm_reacting:
> + rv_remove(reacting);
> +rm_available:
> + rv_remove(available);
> +out_err:
> + return -ENOMEM;
> +}
> --
> 2.35.1

2022-07-17 19:24:47

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH V5 02/16] rv: Add runtime reactors interface

Hi Daniel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on rostedt-trace/for-next]
[also build test WARNING on tip/sched/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
base: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next
config: x86_64-allmodconfig (https://download.01.org/0day-ci/archive/20220718/[email protected]/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.4-39-gce1a6720-dirty
# https://github.com/intel-lab-lkp/linux/commit/aa2ae8ed1dd28e5df7022e89ed27a9a5283647d9
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
git checkout aa2ae8ed1dd28e5df7022e89ed27a9a5283647d9
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/misc/lkdtm/ kernel/trace/rv/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>


sparse warnings: (new ones prefixed by >>)
>> kernel/trace/rv/rv_reactors.c:73:1: sparse: sparse: symbol 'rv_reactors_list' was not declared. Should it be static?
>> kernel/trace/rv/rv_reactors.c:451:19: sparse: sparse: symbol 'rv_nop' was not declared. Should it be static?

--
0-DAY CI Kernel Test Service
https://01.org/lkp

2022-07-18 00:12:19

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH V5 15/16] rv/reactor: Add the printk reactor

Hi Daniel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on rostedt-trace/for-next]
[also build test WARNING on tip/sched/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
base: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next
config: x86_64-allmodconfig (https://download.01.org/0day-ci/archive/20220718/[email protected]/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.4-39-gce1a6720-dirty
# https://github.com/intel-lab-lkp/linux/commit/d1746223447deb1d1646f968512a065a1cd63a9c
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
git checkout d1746223447deb1d1646f968512a065a1cd63a9c
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/misc/lkdtm/ kernel/trace/rv/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>


sparse warnings: (new ones prefixed by >>)
>> kernel/trace/rv/reactor_printk.c:20:19: sparse: sparse: symbol 'rv_printk' was not declared. Should it be static?
>> kernel/trace/rv/reactor_printk.c:26:5: sparse: sparse: symbol 'register_react_printk' was not declared. Should it be static?
>> kernel/trace/rv/reactor_printk.c:32:6: sparse: sparse: symbol 'unregister_react_printk' was not declared. Should it be static?

--
0-DAY CI Kernel Test Service
https://01.org/lkp

2022-07-18 02:32:51

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH V5 16/16] rv/reactor: Add the panic reactor

Hi Daniel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on rostedt-trace/for-next]
[also build test WARNING on tip/sched/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
base: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next
config: x86_64-allmodconfig (https://download.01.org/0day-ci/archive/20220718/[email protected]/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.4-39-gce1a6720-dirty
# https://github.com/intel-lab-lkp/linux/commit/f83faf07d0dad6cfd8fb22ff38b752dd7619bfc0
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
git checkout f83faf07d0dad6cfd8fb22ff38b752dd7619bfc0
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/misc/lkdtm/ kernel/trace/rv/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>


sparse warnings: (new ones prefixed by >>)
>> kernel/trace/rv/reactor_panic.c:21:19: sparse: sparse: symbol 'rv_panic' was not declared. Should it be static?
>> kernel/trace/rv/reactor_panic.c:27:5: sparse: sparse: symbol 'register_react_panic' was not declared. Should it be static?
>> kernel/trace/rv/reactor_panic.c:33:6: sparse: sparse: symbol 'unregister_react_panic' was not declared. Should it be static?

--
0-DAY CI Kernel Test Service
https://01.org/lkp

Subject: Re: [PATCH V5 04/16] rv/include: Add deterministic automata monitor definition via C macros

On 7/17/22 17:18, Tao Zhou wrote:
>> +static int task_mon_slot_##name = RV_PER_TASK_MONITOR_INIT; \
> In patch1, RV_PER_TASK_MONITOR_INIT is defined as:
>
> #define RV_PER_TASK_MONITORS 1
> #define RV_PER_TASK_MONITOR_INIT (RV_PER_TASK_MONITORS)
>
> RV_PER_TASK_MONITOR_INIT is 1 now, seems not the index of the first only
> element in vector. Now no map here, one task has one monitor though if I
> am not wrong.
> So task_mon_slot_##name must be defined to the index of first element.
> Modify the macro definition of RV_PER_TASK_MONITOR_INIT to the index of
> first element in vector.
>
> #define RV_PER_TASK_MONITOR_INIT (RV_PER_TASK_MONITORS) - 1

nop, (RV_PER_TASK_MONITORS) is an invalid vector value, so we can detect things like:
disabling a disabled monitor.

(I forgot to reset it when disabling a monitor... added)

-- Daniel

2022-07-18 08:56:30

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH V5 15/16] rv/reactor: Add the printk reactor

Hi Daniel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on rostedt-trace/for-next]
[also build test WARNING on tip/sched/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
base: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next
config: hexagon-allyesconfig (https://download.01.org/0day-ci/archive/20220718/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 07022e6cf9b5b3baa642be53d0b3c3f1c403dbfd)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/d1746223447deb1d1646f968512a065a1cd63a9c
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
git checkout d1746223447deb1d1646f968512a065a1cd63a9c
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/net/pcs/ kernel/trace/rv/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>

All warnings (new ones prefixed by >>):

>> kernel/trace/rv/reactor_printk.c:26:5: warning: no previous prototype for function 'register_react_printk' [-Wmissing-prototypes]
int register_react_printk(void)
^
kernel/trace/rv/reactor_printk.c:26:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int register_react_printk(void)
^
static
>> kernel/trace/rv/reactor_printk.c:32:6: warning: no previous prototype for function 'unregister_react_printk' [-Wmissing-prototypes]
void unregister_react_printk(void)
^
kernel/trace/rv/reactor_printk.c:32:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void unregister_react_printk(void)
^
static
2 warnings generated.


vim +/register_react_printk +26 kernel/trace/rv/reactor_printk.c

25
> 26 int register_react_printk(void)
27 {
28 rv_register_reactor(&rv_printk);
29 return 0;
30 }
31
> 32 void unregister_react_printk(void)
33 {
34 rv_unregister_reactor(&rv_printk);
35 }
36

--
0-DAY CI Kernel Test Service
https://01.org/lkp

2022-07-18 12:25:20

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH V5 16/16] rv/reactor: Add the panic reactor

Hi Daniel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on rostedt-trace/for-next]
[also build test WARNING on tip/sched/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
base: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next
config: hexagon-allyesconfig (https://download.01.org/0day-ci/archive/20220718/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 07022e6cf9b5b3baa642be53d0b3c3f1c403dbfd)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/f83faf07d0dad6cfd8fb22ff38b752dd7619bfc0
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Daniel-Bristot-de-Oliveira/The-Runtime-Verification-RV-interface/20220714-052220
git checkout f83faf07d0dad6cfd8fb22ff38b752dd7619bfc0
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/net/pcs/ kernel/trace/rv/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>

All warnings (new ones prefixed by >>):

>> kernel/trace/rv/reactor_panic.c:27:5: warning: no previous prototype for function 'register_react_panic' [-Wmissing-prototypes]
int register_react_panic(void)
^
kernel/trace/rv/reactor_panic.c:27:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int register_react_panic(void)
^
static
>> kernel/trace/rv/reactor_panic.c:33:6: warning: no previous prototype for function 'unregister_react_panic' [-Wmissing-prototypes]
void unregister_react_panic(void)
^
kernel/trace/rv/reactor_panic.c:33:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void unregister_react_panic(void)
^
static
2 warnings generated.


vim +/register_react_panic +27 kernel/trace/rv/reactor_panic.c

26
> 27 int register_react_panic(void)
28 {
29 rv_register_reactor(&rv_panic);
30 return 0;
31 }
32
> 33 void unregister_react_panic(void)
34 {
35 rv_unregister_reactor(&rv_panic);
36 }
37

--
0-DAY CI Kernel Test Service
https://01.org/lkp