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 v7:
- Optmize the check for monitoring enabled (Tao)
- add lockdep checks on rv_enable/disable_monitor (Steven)
- Adjusted the "------" of documentation titles (Steven)
- Adjusted turn_monitoring_on(), and added a
turn_monitoring_on_with_reset() (Steven)
- Moved all tracepoint_synchronize_unregister() to run with
interface lock taken, and added a comment about it (Steven)
- lockdep, WARN, and call reactor_cleanup_monitor() (Steven)
- Improve comments on synchronization (Steven)
- pop, I could've had a v-8 Joke (Daniel)
Changes from v6:
- Remove lock protection when reading static data (Steven)
- Add lock protection in disable_all_monitors() (Steven)
- Re-arrange enable_monitor (Steven/Tao)
- Fix monitor_desc_read_data() Description (Tao)
- Wait for tracepoint_synchronize_unregister() anytime a monitor
is Disabled (daniel)
- Add memory barriers around monitoring_on and reacting_on (Steven)
- Make rv reactor name and description const char * (Tao)
- Append missing _##name for some da_automata functions/variables (Steven)
- rv_unregister_monitor() will disable the monitor if necessary, and
take care of synchronization (Daniel)
- Fixed da_monitor_instrumentation.rst (Tao)
- Fix !CONFIG_Rv_REACTORS (kbuild test)
- Moved struct rv/rv.h to linux/rv.h (Daniel)
- Add rv_ prefix on get/put task slot (Daniel)
Changes from v5:
- Add task monitor slot checks (Daniel/Tao)
- Reset the monitors only after initializing the data (Daniel)
- Add static for static data (Daniel/0-day)
- Change start/stop *functions to enable/disable (like the user-
interface (Daniel)
- s/init/start/ for the functions starting the monitoring (Daniel)
- Access monitoring_on and reacting_on via functions (Daniel)
- Improved vector access checks (Tao)
- cleanups (Daniel/Tao)
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 | 171 ++++
.../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 | 231 +++++
include/linux/rv.h | 70 ++
include/linux/sched.h | 11 +
include/rv/automata.h | 75 ++
include/rv/da_monitor.h | 543 ++++++++++++
include/rv/instrumentation.h | 29 +
include/trace/events/rv.h | 142 ++++
kernel/fork.c | 14 +
kernel/trace/Kconfig | 2 +
kernel/trace/Makefile | 1 +
kernel/trace/rv/Kconfig | 78 ++
kernel/trace/rv/Makefile | 8 +
kernel/trace/rv/monitors/wip/wip.c | 88 ++
kernel/trace/rv/monitors/wip/wip.h | 46 +
kernel/trace/rv/monitors/wwnr/wwnr.c | 87 ++
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 | 799 ++++++++++++++++++
kernel/trace/rv/rv.h | 69 ++
kernel/trace/rv/rv_reactors.c | 508 +++++++++++
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 | 91 ++
.../dot2/dot2k_templates/main_per_cpu.c | 91 ++
.../dot2/dot2k_templates/main_per_task.c | 91 ++
tools/verification/models/wip.dot | 16 +
tools/verification/models/wwnr.dot | 16 +
41 files changed, 4569 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/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
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 b259d6e8dc7c..e82d5015e6ab 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -60,3 +60,11 @@ 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..31899f953af4
--- /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);
+}
+
+static struct rv_reactor rv_printk = {
+ .name = "printk",
+ .description = "prints the exception msg to the kernel message log.",
+ .react = rv_printk_reaction
+};
+
+static int register_react_printk(void)
+{
+ rv_register_reactor(&rv_printk);
+ return 0;
+}
+
+static 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
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..0dbdcd1e62b9
--- /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_start_event_$(MONITOR_NAME)($(event from event enum));
+ da_handle_start_run_event_$(MONITOR_NAME)($(event from event enum));
+
+The function ``da_handle_event_$(MONITOR_NAME)()`` is the regular case where
+the event will be processed if the monitor is processing events.
+
+When a monitor is enabled, it is placed in the initial state of the automata.
+However, the monitor does not know if the system is in the *initial state*.
+
+The ``da_handle_start_event_$(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_start_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_start_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 f79a7737b39f..603ba3064bb4 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 d85f755e3bc7..016550fccf1f 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
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..eb9e636809a0
--- /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_initial_state_##name - return the automaton's initial state \
+ */ \
+static inline type model_get_initial_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
transform .dot file into kernel rv monitor
usage: dot2k [-h] -d DOT_FILE -t MONITOR_TYPE [-n MODEL_NAME] [-D DESCRIPTION]
optional arguments:
-h, --help show this help message and exit
-d DOT_FILE, --dot DOT_FILE
-t MONITOR_TYPE, --monitor_type MONITOR_TYPE
-n MODEL_NAME, --model_name MODEL_NAME
-D DESCRIPTION, --description DESCRIPTION
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 | 5 +
tools/verification/dot2/dot2k | 44 +++++
tools/verification/dot2/dot2k.py | 174 ++++++++++++++++++
.../dot2/dot2k_templates/main_global.c | 91 +++++++++
.../dot2/dot2k_templates/main_per_cpu.c | 91 +++++++++
.../dot2/dot2k_templates/main_per_task.c | 91 +++++++++
6 files changed, 496 insertions(+)
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
diff --git a/tools/verification/dot2/Makefile b/tools/verification/dot2/Makefile
index 235d182f6b2c..021beb07a521 100644
--- a/tools/verification/dot2/Makefile
+++ b/tools/verification/dot2/Makefile
@@ -19,3 +19,8 @@ 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)/
+ $(INSTALL) dot2k.py -D -m 644 $(DESTDIR)$(PYLIB)/dot2/dot2k.py
+ $(INSTALL) dot2k -D -m 755 $(DESTDIR)$(bindir)/
+
+ mkdir -p ${miscdir}/
+ cp -rp dot2k_templates $(DESTDIR)$(miscdir)/
diff --git a/tools/verification/dot2/dot2k b/tools/verification/dot2/dot2k
new file mode 100644
index 000000000000..69106f4b7682
--- /dev/null
+++ b/tools/verification/dot2/dot2k
@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+#
+# dot2k: transform dot files into a monitor for the Linux kernel.
+
+if __name__ == '__main__':
+ from dot2.dot2k import dot2k
+ import argparse
+ import ntpath
+ import os
+ import platform
+ import sys
+ import sys
+ import argparse
+
+ parser = argparse.ArgumentParser(description='transform .dot file into kernel rv monitor')
+ parser.add_argument('-d', "--dot", dest="dot_file", required=True)
+ parser.add_argument('-t', "--monitor_type", dest="monitor_type", required=True)
+ parser.add_argument('-n', "--model_name", dest="model_name", required=False)
+ parser.add_argument("-D", "--description", dest="description", required=False)
+ params = parser.parse_args()
+
+ print("Opening and parsing the dot file %s" % params.dot_file)
+ try:
+ monitor=dot2k(params.dot_file, params.monitor_type)
+ except Exception as e:
+ print('Error: '+ str(e))
+ print("Sorry : :-(")
+ sys.exit(1)
+
+ # easier than using argparse action.
+ if params.model_name != None:
+ print(params.model_name)
+
+ print("Writing the monitor into the directory %s" % monitor.name)
+ monitor.print_files()
+ print("Almost done, checklist")
+ print(" - Edit the %s/%s.c to add the instrumentation" % (monitor.name, monitor.name))
+ print(" - Edit include/trace/events/rv.h to add the tracepoint entry")
+ print(" - Move it to the kernel's monitor directory")
+ print(" - Edit kernel/trace/rv/Makefile")
+ print(" - Edit kernel/trace/rv/Kconfig")
diff --git a/tools/verification/dot2/dot2k.py b/tools/verification/dot2/dot2k.py
new file mode 100644
index 000000000000..d85f755e3bc7
--- /dev/null
+++ b/tools/verification/dot2/dot2k.py
@@ -0,0 +1,174 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+#
+# dot2k: transform dot files into a monitor for the Linux kernel.
+
+from dot2.dot2c import Dot2c
+import platform
+import os
+
+class dot2k(Dot2c):
+ monitor_types = { "global" : 1, "per_cpu" : 2, "per_task" : 3 }
+ monitor_templates_dir = "dot2k/rv_templates/"
+ monitor_type = "per_cpu"
+
+ def __init__(self, file_path, MonitorType):
+ super().__init__(file_path)
+
+ self.monitor_type = self.monitor_types.get(MonitorType)
+ if self.monitor_type == None:
+ raise Exception("Unknown monitor type: %s" % MonitorType)
+
+ self.monitor_type = MonitorType
+ self.__fill_rv_templates_dir()
+ self.main_c = self.__open_file(self.monitor_templates_dir + "main_" + MonitorType + ".c")
+ self.enum_suffix = "_%s" % self.name
+
+ def __fill_rv_templates_dir(self):
+
+ if os.path.exists(self.monitor_templates_dir) == True:
+ return
+
+ if platform.system() != "Linux":
+ raise Exception("I can only run on Linux.")
+
+ kernel_path = "/lib/modules/%s/build/tools/verification/dot2/dot2k_templates/" % (platform.release())
+
+ if os.path.exists(kernel_path) == True:
+ self.monitor_templates_dir = kernel_path
+ return
+
+ if os.path.exists("/usr/share/dot2/dot2k_templates/") == True:
+ self.monitor_templates_dir = "/usr/share/dot2/dot2k_templates/"
+ return
+
+ raise Exception("Could not find the template directory, do you have the kernel source installed?")
+
+
+ def __open_file(self, path):
+ try:
+ fd = open(path)
+ except OSError:
+ raise Exception("Cannot open the file: %s" % path)
+
+ content = fd.read()
+
+ return content
+
+ def __buff_to_string(self, buff):
+ string = ""
+
+ for line in buff:
+ string = string + line + "\n"
+
+ # cut off the last \n
+ return string[:-1]
+
+ def fill_tracepoint_handlers_skel(self):
+ buff = []
+ for event in self.events:
+ buff.append("static void handle_%s(void *data, /* XXX: fill header */)" % event)
+ buff.append("{")
+ if self.monitor_type == "per_task":
+ buff.append("\tstruct task_struct *p = /* XXX: how do I get p? */;");
+ buff.append("\tda_handle_event_%s(p, %s%s);" % (self.name, event, self.enum_suffix));
+ else:
+ buff.append("\tda_handle_event_%s(%s%s);" % (self.name, event, self.enum_suffix));
+ buff.append("}")
+ buff.append("")
+ return self.__buff_to_string(buff)
+
+ def fill_tracepoint_attach_probe(self):
+ buff = []
+ for event in self.events:
+ buff.append("\trv_attach_trace_probe(\"%s\", /* XXX: tracepoint */, handle_%s);" % (self.name, event))
+ return self.__buff_to_string(buff)
+
+ def fill_tracepoint_detach_helper(self):
+ buff = []
+ for event in self.events:
+ buff.append("\trv_detach_trace_probe(\"%s\", /* XXX: tracepoint */, handle_%s);" % (self.name, event))
+ return self.__buff_to_string(buff)
+
+ def fill_main_c(self):
+ main_c = self.main_c
+ min_type = self.get_minimun_type()
+ nr_events = self.events.__len__()
+ tracepoint_handlers = self.fill_tracepoint_handlers_skel()
+ tracepoint_attach = self.fill_tracepoint_attach_probe()
+ tracepoint_detach = self.fill_tracepoint_detach_helper()
+
+ main_c = main_c.replace("MIN_TYPE", min_type)
+ main_c = main_c.replace("MODEL_NAME", self.name)
+ main_c = main_c.replace("NR_EVENTS", str(nr_events))
+ main_c = main_c.replace("TRACEPOINT_HANDLERS_SKEL", tracepoint_handlers)
+ main_c = main_c.replace("TRACEPOINT_ATTACH", tracepoint_attach)
+ main_c = main_c.replace("TRACEPOINT_DETACH", tracepoint_detach)
+
+ return main_c
+
+ def fill_model_h_header(self):
+ buff = []
+ buff.append("/*")
+ buff.append(" * Automatically generated C representation of %s automaton" % (self.name))
+ buff.append(" * For further information about this format, see kernel documentation:")
+ buff.append(" * Documentation/trace/rv/deterministic_automata.rst")
+ buff.append(" */")
+ buff.append("")
+
+ return buff
+
+ def fill_model_h(self):
+ #
+ # Adjust the definition names
+ #
+ self.enum_states_def = "states_%s" % self.name
+ self.enum_events_def = "events_%s" % self.name
+ self.struct_automaton_def = "automaton_%s" % self.name
+ self.var_automaton_def = "automaton_%s" % self.name
+
+ buff = self.fill_model_h_header()
+ buff += self.format_model()
+
+ return self.__buff_to_string(buff)
+
+ def __create_directory(self):
+ try:
+ os.mkdir(self.name)
+ except FileExistsError:
+ return
+ except:
+ print("Fail creating the output dir: %s" % self.name)
+
+ def __create_file(self, file_name, content):
+ path = "%s/%s" % (self.name, file_name)
+ try:
+ file = open(path, 'w')
+ except FileExistsError:
+ return
+ except:
+ print("Fail creating file: %s" % path)
+
+ file.write(content)
+
+ file.close()
+
+ def __get_main_name(self):
+ path = "%s/%s" % (self.name, "main.c")
+ if os.path.exists(path) == False:
+ return "main.c"
+ return "__main.c"
+
+ def print_files(self):
+ main_c = self.fill_main_c()
+ model_h = self.fill_model_h()
+
+ self.__create_directory()
+
+ path = "%s.c" % self.name
+ self.__create_file(path, main_c)
+
+ path = "%s.h" % self.name
+ self.__create_file(path, model_h)
diff --git a/tools/verification/dot2/dot2k_templates/main_global.c b/tools/verification/dot2/dot2k_templates/main_global.c
new file mode 100644
index 000000000000..f4b712dbc92e
--- /dev/null
+++ b/tools/verification/dot2/dot2k_templates/main_global.c
@@ -0,0 +1,91 @@
+// 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 "MODEL_NAME"
+
+/*
+ * XXX: include required tracepoint headers, e.g.,
+ * #include <trace/events/sched.h>
+ */
+#include <trace/events/rv.h>
+
+/*
+ * This is the self-generated part of the monitor. Generally, there is no need
+ * to touch this section.
+ */
+#include "MODEL_NAME.h"
+
+/*
+ * Declare the deterministic automata monitor.
+ *
+ * The rv monitor reference is needed for the monitor declaration.
+ */
+struct rv_monitor rv_MODEL_NAME;
+DECLARE_DA_MON_GLOBAL(MODEL_NAME, MIN_TYPE);
+
+/*
+ * 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.
+ *
+ */
+TRACEPOINT_HANDLERS_SKEL
+static int enable_MODEL_NAME(void)
+{
+ int retval;
+
+ retval = da_monitor_init_MODEL_NAME();
+ if (retval)
+ return retval;
+
+TRACEPOINT_ATTACH
+
+ return 0;
+}
+
+static void disable_MODEL_NAME(void)
+{
+ rv_MODEL_NAME.enabled = 0;
+
+TRACEPOINT_DETACH
+
+ da_monitor_destroy_MODEL_NAME();
+}
+
+/*
+ * This is the monitor register section.
+ */
+struct rv_monitor rv_MODEL_NAME = {
+ .name = "MODEL_NAME",
+ .description = "auto-generated MODEL_NAME",
+ .enable = enable_MODEL_NAME,
+ .disable = disable_MODEL_NAME,
+ .reset = da_monitor_reset_all_MODEL_NAME,
+ .enabled = 0,
+};
+
+static int register_MODEL_NAME(void)
+{
+ rv_register_monitor(&rv_MODEL_NAME);
+ return 0;
+}
+
+static void unregister_MODEL_NAME(void)
+{
+ rv_unregister_monitor(&rv_MODEL_NAME);
+}
+
+module_init(register_MODEL_NAME);
+module_exit(unregister_MODEL_NAME);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("dot2k: auto-generated");
+MODULE_DESCRIPTION("MODEL_NAME");
diff --git a/tools/verification/dot2/dot2k_templates/main_per_cpu.c b/tools/verification/dot2/dot2k_templates/main_per_cpu.c
new file mode 100644
index 000000000000..4080d1ca3354
--- /dev/null
+++ b/tools/verification/dot2/dot2k_templates/main_per_cpu.c
@@ -0,0 +1,91 @@
+// 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 "MODEL_NAME"
+
+/*
+ * XXX: include required tracepoint headers, e.g.,
+ * #include <linux/trace/events/sched.h>
+ */
+#include <trace/events/rv.h>
+
+/*
+ * This is the self-generated part of the monitor. Generally, there is no need
+ * to touch this section.
+ */
+#include "MODEL_NAME.h"
+
+/*
+ * Declare the deterministic automata monitor.
+ *
+ * The rv monitor reference is needed for the monitor declaration.
+ */
+struct rv_monitor rv_MODEL_NAME;
+DECLARE_DA_MON_PER_CPU(MODEL_NAME, MIN_TYPE);
+
+/*
+ * 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.
+ *
+ */
+TRACEPOINT_HANDLERS_SKEL
+static int enable_MODEL_NAME(void)
+{
+ int retval;
+
+ retval = da_monitor_init_MODEL_NAME();
+ if (retval)
+ return retval;
+
+TRACEPOINT_ATTACH
+
+ return 0;
+}
+
+static void disable_MODEL_NAME(void)
+{
+ rv_MODEL_NAME.enabled = 0;
+
+TRACEPOINT_DETACH
+
+ da_monitor_destroy_MODEL_NAME();
+}
+
+/*
+ * This is the monitor register section.
+ */
+struct rv_monitor rv_MODEL_NAME = {
+ .name = "MODEL_NAME",
+ .description = "auto-generated MODEL_NAME",
+ .enable = enable_MODEL_NAME,
+ .disable = disable_MODEL_NAME,
+ .reset = da_monitor_reset_all_MODEL_NAME,
+ .enabled = 0,
+};
+
+static int register_MODEL_NAME(void)
+{
+ rv_register_monitor(&rv_MODEL_NAME);
+ return 0;
+}
+
+static void unregister_MODEL_NAME(void)
+{
+ rv_unregister_monitor(&rv_MODEL_NAME);
+}
+
+module_init(register_MODEL_NAME);
+module_exit(unregister_MODEL_NAME);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("dot2k: auto-generated");
+MODULE_DESCRIPTION("MODEL_NAME");
diff --git a/tools/verification/dot2/dot2k_templates/main_per_task.c b/tools/verification/dot2/dot2k_templates/main_per_task.c
new file mode 100644
index 000000000000..89197175384f
--- /dev/null
+++ b/tools/verification/dot2/dot2k_templates/main_per_task.c
@@ -0,0 +1,91 @@
+// 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 "MODEL_NAME"
+
+/*
+ * XXX: include required tracepoint headers, e.g.,
+ * #include <linux/trace/events/sched.h>
+ */
+#include <trace/events/rv.h>
+
+/*
+ * This is the self-generated part of the monitor. Generally, there is no need
+ * to touch this section.
+ */
+#include "MODEL_NAME.h"
+
+/*
+ * Declare the deterministic automata monitor.
+ *
+ * The rv monitor reference is needed for the monitor declaration.
+ */
+struct rv_monitor rv_MODEL_NAME;
+DECLARE_DA_MON_PER_TASK(MODEL_NAME, MIN_TYPE);
+
+/*
+ * 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.
+ *
+ */
+TRACEPOINT_HANDLERS_SKEL
+static int enable_MODEL_NAME(void)
+{
+ int retval;
+
+ retval = da_monitor_init_MODEL_NAME();
+ if (retval)
+ return retval;
+
+TRACEPOINT_ATTACH
+
+ return 0;
+}
+
+static void disable_MODEL_NAME(void)
+{
+ rv_MODEL_NAME.enabled = 0;
+
+TRACEPOINT_DETACH
+
+ da_monitor_destroy_MODEL_NAME();
+}
+
+/*
+ * This is the monitor register section.
+ */
+struct rv_monitor rv_MODEL_NAME = {
+ .name = "MODEL_NAME",
+ .description = "auto-generated MODEL_NAME",
+ .enable = enable_MODEL_NAME,
+ .disable = disable_MODEL_NAME,
+ .reset = da_monitor_reset_all_MODEL_NAME,
+ .enabled = 0,
+};
+
+static int register_MODEL_NAME(void)
+{
+ rv_register_monitor(&rv_MODEL_NAME);
+ return 0;
+}
+
+static void unregister_MODEL_NAME(void)
+{
+ rv_unregister_monitor(&rv_MODEL_NAME);
+}
+
+module_init(register_MODEL_NAME);
+module_exit(unregister_MODEL_NAME);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("dot2k: auto-generated");
+MODULE_DESCRIPTION("MODEL_NAME");
--
2.35.1
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 | 10 +
include/rv/da_monitor.h | 540 ++++++++++++++++++++++++++++++++++++++
include/trace/events/rv.h | 120 +++++++++
kernel/fork.c | 14 +
kernel/trace/rv/Kconfig | 11 +
kernel/trace/rv/rv.c | 5 +
6 files changed, 700 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 dcce56987cf7..978fd62c1ff5 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -7,7 +7,16 @@
#ifndef _LINUX_RV_H
#define _LINUX_RV_H
+#define MAX_DA_NAME_LEN 24
+
#ifdef CONFIG_RV
+/*
+ * 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.
@@ -22,6 +31,7 @@
* Futher monitor types are expected, so make this a union.
*/
union rv_task_monitor {
+ struct da_monitor da_mon;
};
#ifdef CONFIG_RV_REACTORS
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
new file mode 100644
index 000000000000..f79a7737b39f
--- /dev/null
+++ b/include/rv/da_monitor.h
@@ -0,0 +1,540 @@
+/* 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>
+#include <linux/bug.h>
+
+#ifdef CONFIG_RV_REACTORS
+
+#define DECLARE_RV_REACTING_HELPERS(name, type) \
+static char REACT_MSG_##name[1024]; \
+ \
+static inline char *format_react_msg_##name(type curr_state, type event) \
+{ \
+ snprintf(REACT_MSG_##name, 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_##name; \
+} \
+ \
+static void cond_react_##name(char *msg) \
+{ \
+ if (rv_##name.react) \
+ rv_##name.react(msg); \
+} \
+ \
+static bool rv_reacting_on_##name(void) \
+{ \
+ return rv_reacting_on(); \
+}
+
+#else /* CONFIG_RV_REACTOR */
+
+#define DECLARE_RV_REACTING_HELPERS(name, type) \
+static inline char *format_react_msg_##name(type curr_state, type event) \
+{ \
+ return NULL; \
+} \
+ \
+static void cond_react_##name(char *msg) \
+{ \
+ return; \
+} \
+ \
+static bool rv_reacting_on_##name(void) \
+{ \
+ return 0; \
+}
+#endif
+
+/*
+ * Generic helpers for all types of deterministic automata monitors.
+ */
+#define DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+ \
+DECLARE_RV_REACTING_HELPERS(name, type) \
+ \
+/* \
+ * 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_initial_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; \
+} \
+ \
+/* \
+ * da_monitor_enabled_##name - checks if the monitor is enabled \
+ */ \
+static inline bool da_monitor_enabled_##name(void) \
+{ \
+ /* global switch */ \
+ if (unlikely(!rv_monitoring_on())) \
+ return 0; \
+ \
+ /* monitor enabled */ \
+ if (unlikely(!rv_##name.enabled)) \
+ return 0; \
+ \
+ return 1; \
+} \
+ \
+/* \
+ * da_monitor_handling_event_##name - checks if the monitor is ready to handle events \
+ */ \
+static inline bool da_monitor_handling_event_##name(struct da_monitor *da_mon) \
+{ \
+ \
+ if (!da_monitor_enabled_##name()) \
+ return 0; \
+ \
+ /* monitor is actually monitoring */ \
+ if (unlikely(!da_monitoring_##name(da_mon))) \
+ return 0; \
+ \
+ return 1; \
+}
+
+/*
+ * 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 (rv_reacting_on_##name()) \
+ cond_react_##name(format_react_msg_##name(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 bool 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 (rv_reacting_on_##name()) \
+ cond_react_##name(format_react_msg_##name(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_get_monitor_##name()); \
+} \
+ \
+/* \
+ * da_monitor_init_##name - initialize a monitor \
+ */ \
+static inline int da_monitor_init_##name(void) \
+{ \
+ da_monitor_reset_all_##name(); \
+ 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) \
+{ \
+ da_monitor_reset_all_##name(); \
+ 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) \
+{ \
+ int slot; \
+ \
+ slot = rv_get_task_monitor_slot(); \
+ if (slot < 0 || slot >= RV_PER_TASK_MONITOR_INIT) \
+ return slot; \
+ \
+ task_mon_slot_##name = slot; \
+ \
+ da_monitor_reset_all_##name(); \
+ 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; \
+ } \
+ rv_put_task_monitor_slot(task_mon_slot_##name); \
+ task_mon_slot_##name = RV_PER_TASK_MONITOR_INIT; \
+ 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) \
+{ \
+ bool retval; \
+ \
+ 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(); \
+ bool retval; \
+ \
+ retval = da_monitor_handling_event_##name(da_mon); \
+ if (!retval) \
+ return; \
+ \
+ __da_handle_event_##name(da_mon, event); \
+} \
+ \
+/* \
+ * da_handle_start_event_##name - start monitoring or handle event \
+ * \
+ * This function is used to 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_start_event_##name(enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (!da_monitor_enabled_##name()) \
+ return 0; \
+ \
+ da_mon = da_get_monitor_##name(); \
+ \
+ if (unlikely(!da_monitoring_##name(da_mon))) { \
+ da_monitor_start_##name(da_mon); \
+ return 0; \
+ } \
+ \
+ __da_handle_event_##name(da_mon, event); \
+ \
+ return 1; \
+} \
+ \
+/* \
+ * da_handle_start_run_event_##name - start monitoring and handle event \
+ * \
+ * This function is used to 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_start_run_event_##name(enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (!da_monitor_enabled_##name()) \
+ return 0; \
+ \
+ 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 1; \
+}
+
+/*
+ * 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) \
+{ \
+ bool retval; \
+ \
+ 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); \
+ bool retval; \
+ \
+ retval = da_monitor_handling_event_##name(da_mon); \
+ if (!retval) \
+ return; \
+ \
+ __da_handle_event_##name(da_mon, tsk, event); \
+} \
+ \
+/* \
+ * da_handle_start_event_##name - start monitoring or handle event \
+ * \
+ * This function is used to 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_start_event_##name(struct task_struct *tsk, enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (!da_monitor_enabled_##name()) \
+ return 0; \
+ \
+ da_mon = da_get_monitor_##name(tsk); \
+ \
+ if (unlikely(!da_monitoring_##name(da_mon))) { \
+ da_monitor_start_##name(da_mon); \
+ return 0; \
+ } \
+ \
+ __da_handle_event_##name(da_mon, tsk, event); \
+ \
+ return 1; \
+}
+
+/*
+ * 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/trace/events/rv.h b/include/trace/events/rv.h
new file mode 100644
index 000000000000..20a2e09c6416
--- /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..8714800e22ad 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -1,5 +1,16 @@
# SPDX-License-Identifier: GPL-2.0-only
#
+config DA_MON_EVENTS
+ bool
+
+config DA_MON_EVENTS_IMPLICIT
+ select DA_MON_EVENTS
+ bool
+
+config DA_MON_EVENTS_ID
+ select DA_MON_EVENTS
+ bool
+
menuconfig RV
bool "Runtime Verification"
depends on TRACING
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
index 45cf64eb2600..df6678c86334 100644
--- a/kernel/trace/rv/rv.c
+++ b/kernel/trace/rv/rv.c
@@ -140,6 +140,11 @@
#include <linux/init.h>
#include <linux/slab.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
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 e82d5015e6ab..831779607e84 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -68,3 +68,11 @@ 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..b698d05dd069
--- /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);
+}
+
+static struct rv_reactor rv_panic = {
+ .name = "panic",
+ .description = "panic the system if an exception is found.",
+ .react = rv_panic_reaction
+};
+
+static int register_react_panic(void)
+{
+ rv_register_reactor(&rv_panic);
+ return 0;
+}
+
+static 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
Instrumentation helper functions to facilitate the instrumentation of
auto-generated RV monitors create by dot2k.
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/instrumentation.h | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
create mode 100644 include/rv/instrumentation.h
diff --git a/include/rv/instrumentation.h b/include/rv/instrumentation.h
new file mode 100644
index 000000000000..d4e7a02ede1a
--- /dev/null
+++ b/include/rv/instrumentation.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <[email protected]>
+ *
+ * Helper functions to facilitate the instrumentation of auto-generated
+ * RV monitors create by dot2k.
+ *
+ * The dot2k tool is available at tools/verification/dot2/
+ */
+
+#include <linux/ftrace.h>
+
+/*
+ * rv_attach_trace_probe - check and attach a handler function to a tracepoint
+ */
+#define rv_attach_trace_probe(monitor, tp, rv_handler) \
+ do { \
+ check_trace_callback_type_##tp(rv_handler); \
+ WARN_ONCE(register_trace_##tp(rv_handler, NULL), \
+ "fail attaching " #monitor " " #tp "handler"); \
+ } while (0)
+
+/*
+ * rv_detach_trace_probe - detach a handler function to a tracepoint
+ */
+#define rv_detach_trace_probe(monitor, tp, rv_handler) \
+ do { \
+ unregister_trace_##tp(rv_handler, NULL); \
+ } while (0)
--
2.35.1
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 | 17 ++
kernel/trace/rv/Kconfig | 11 +
kernel/trace/rv/Makefile | 1 +
kernel/trace/rv/rv.c | 8 +
kernel/trace/rv/rv.h | 35 +++
kernel/trace/rv/rv_reactors.c | 508 ++++++++++++++++++++++++++++++++++
6 files changed, 580 insertions(+)
create mode 100644 kernel/trace/rv/rv_reactors.c
diff --git a/include/linux/rv.h b/include/linux/rv.h
index d8fa9e8be94a..dcce56987cf7 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -24,6 +24,14 @@
union rv_task_monitor {
};
+#ifdef CONFIG_RV_REACTORS
+struct rv_reactor {
+ const char *name;
+ const char *description;
+ void (*react)(char *msg);
+};
+#endif
+
struct rv_monitor {
const char *name;
const char *description;
@@ -31,6 +39,9 @@ struct rv_monitor {
int (*enable)(void);
void (*disable)(void);
void (*reset)(void);
+#ifdef CONFIG_RV_REACTORS
+ void (*react)(char *msg);
+#endif
};
bool rv_monitoring_on(void);
@@ -39,5 +50,11 @@ int rv_register_monitor(struct rv_monitor *monitor);
int rv_get_task_monitor_slot(void);
void rv_put_task_monitor_slot(int slot);
+#ifdef CONFIG_RV_REACTORS
+bool rv_reacting_on(void);
+int rv_unregister_reactor(struct rv_reactor *reactor);
+int rv_register_reactor(struct rv_reactor *reactor);
+#endif /* CONFIG_RV_REACTORS */
+
#endif /* CONFIG_RV */
#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 e1179a3bcc0c..45cf64eb2600 100644
--- a/kernel/trace/rv/rv.c
+++ b/kernel/trace/rv/rv.c
@@ -353,6 +353,10 @@ static int create_monitor_dir(struct rv_monitor_def *mdef)
goto out_remove_root;
}
+ retval = reactor_populate_monitor(mdef);
+ if (retval)
+ goto out_remove_root;
+
return 0;
out_remove_root:
@@ -748,6 +752,7 @@ int rv_unregister_monitor(struct rv_monitor *monitor)
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)
@@ -771,6 +776,9 @@ int __init rv_init_interface(void)
&monitoring_on_fops);
if (!tmp)
goto out_err;
+ retval = init_rv_reactors(rv_root.root_dir);
+ if (retval)
+ goto out_err;
turn_monitoring_on();
diff --git a/kernel/trace/rv/rv.h b/kernel/trace/rv/rv.h
index 47643840116e..a284a369fee0 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;
};
@@ -32,3 +46,24 @@ struct dentry *get_monitors_root(void);
int init_rv_monitors(struct dentry *root_dir);
int rv_disable_monitor(struct rv_monitor_def *mdef);
int rv_enable_monitor(struct rv_monitor_def *mdef);
+
+#ifdef CONFIG_RV_REACTORS
+int reactor_populate_monitor(struct rv_monitor_def *mdef);
+void reactor_cleanup_monitor(struct rv_monitor_def *mdef);
+int init_rv_reactors(struct dentry *root_dir);
+#else
+static inline int reactor_populate_monitor(struct rv_monitor_def *mdef)
+{
+ return 0;
+}
+
+static inline void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+{
+ return;
+}
+
+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..a6522c196382
--- /dev/null
+++ b/kernel/trace/rv/rv_reactors.c
@@ -0,0 +1,508 @@
+// 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"
+
+/*
+ * Interface for the reactor register.
+ */
+static 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's 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 void monitor_swap_reactors(struct rv_monitor_def *mdef, struct rv_reactor_def *rdef,
+ bool reacting)
+{
+ bool monitor_enabled;
+
+ /* nothing to do */
+ if (mdef->rdef == rdef)
+ return;
+
+ monitor_enabled = mdef->monitor->enabled;
+ if (monitor_enabled)
+ rv_disable_monitor(mdef);
+
+ /* swap reactor's usage */
+ mdef->rdef->counter--;
+ rdef->counter++;
+
+ mdef->rdef = rdef;
+ mdef->reacting = reacting;
+ mdef->monitor->react = rdef->reactor->react;
+
+ if (monitor_enabled)
+ rv_enable_monitor(mdef);
+}
+
+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 enable;
+ char *ptr;
+ int len;
+
+ if (count < 1 || count > MAX_RV_REACTOR_NAME_SIZE + 1)
+ return -EINVAL;
+
+ memset(buff, 0, sizeof(buff));
+
+ retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf, count);
+ if (retval < 0)
+ 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;
+
+ list_for_each_entry(rdef, &rv_reactors_list, list) {
+ if (strcmp(ptr, rdef->reactor->name) != 0)
+ continue;
+
+ if (rdef == get_reactor_rdef_by_name("nop"))
+ enable = false;
+ else
+ enable = true;
+
+ monitor_swap_reactors(mdef, rdef, enable);
+
+ retval = count;
+ break;
+ }
+
+ mutex_unlock(&rv_interface_lock);
+
+ return retval;
+}
+
+/*
+ * available_reactors interface.
+ */
+static int monitor_reactors_open(struct inode *inode, struct file *file)
+{
+ 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 bool __read_mostly reacting_on;
+
+/**
+ * rv_reacting_on - checks if reacting is on
+ *
+ * Returns 1 if on, 0 otherwise.
+ */
+bool rv_reacting_on(void)
+{
+ /* Ensures that concurrent monitors read consistent reacting_on */
+ smp_rmb();
+ return READ_ONCE(reacting_on);
+}
+
+static ssize_t reacting_on_read_data(struct file *filp,
+ char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char *buff;
+
+ buff = rv_reacting_on() ? "1\n" : "0\n";
+
+ return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
+}
+
+static void turn_reacting_off(void)
+{
+ WRITE_ONCE(reacting_on, false);
+ /* Ensures that concurrent monitors read consistent reacting_on */
+ smp_wmb();
+}
+
+static void turn_reacting_on(void)
+{
+ WRITE_ONCE(reacting_on, true);
+ /* Ensures that concurrent monitors read consistent reacting_on */
+ smp_wmb();
+}
+
+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();
+
+ /*
+ * Wait for the execution of all events to finish
+ * before returning to user-space.
+ */
+ tracepoint_synchronize_unregister();
+
+ 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,
+};
+
+/**
+ * reactor_populate_monitor - creates per monitor reactors file
+ * @mdef: monitor's definition.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int reactor_populate_monitor(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->rdef->counter++;
+ mdef->reacting = false;
+
+ return 0;
+}
+
+/**
+ * reactor_cleanup_monitor - cleanup a monitor reference
+ * @mdef: monitor's definition.
+ */
+void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+{
+ lockdep_assert_held(&rv_interface_lock);
+ mdef->rdef->counter--;
+ WARN_ON_ONCE(mdef->rdef->counter < 0);
+}
+
+/*
+ * Nop reactor register
+ */
+static void rv_nop_reaction(char *msg)
+{
+}
+
+static struct rv_reactor rv_nop = {
+ .name = "nop",
+ .description = "no-operation reactor: do nothing.",
+ .react = rv_nop_reaction
+};
+
+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;
+
+ turn_reacting_on();
+
+ return 0;
+
+rm_reacting:
+ rv_remove(reacting);
+rm_available:
+ rv_remove(available);
+out_err:
+ return -ENOMEM;
+}
--
2.35.1
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..a95763438c48
--- /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 20a2e09c6416..e972f27d8df3 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 0d9552b406c6..e50f3346164a 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -25,6 +25,19 @@ 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 79a054ca0cde..83cace53b9fa 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_start_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 enable_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_enable, handle_preempt_enable);
+ rv_attach_trace_probe("wip", sched_waking, handle_sched_waking);
+ rv_attach_trace_probe("wip", preempt_disable, handle_preempt_disable);
return 0;
}
@@ -71,19 +53,16 @@ static void disable_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.",
.enable = enable_wip,
.disable = disable_wip,
.reset = da_monitor_reset_all_wip,
@@ -105,5 +84,5 @@ 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
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
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 | 87 +++++++++++++++++++++++++
kernel/trace/rv/monitors/wwnr/wwnr.h | 46 +++++++++++++
tools/verification/models/wwnr.dot | 16 +++++
8 files changed, 220 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..80f1777b85aa
--- /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 e972f27d8df3..56592da9301c 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 e50f3346164a..b259d6e8dc7c 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -38,6 +38,18 @@ 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..599225d9cf38
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.c
@@ -0,0 +1,87 @@
+// 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_start_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 enable_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 disable_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.",
+ .enable = enable_wwnr,
+ .disable = disable_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)
+{
+ 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
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 | 231 ++++++++++++++++++
kernel/trace/rv/Kconfig | 3 +
kernel/trace/rv/rv.c | 3 +
5 files changed, 247 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..c46b6149470e
--- /dev/null
+++ b/Documentation/trace/rv/runtime-verification.rst
@@ -0,0 +1,231 @@
+====================
+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 reaction
+
+**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 8714800e22ad..0d9552b406c6 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -22,6 +22,9 @@ 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 df6678c86334..6c97cc2d754a 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
On Wed, Jul 27, 2022 at 07:11:30PM +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
s/switch/switcher/
s/disabling/enabling\/disabling/
[...]
> + * "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
s/switch/switcher/
s/disabling/enabling\/disabling/
[...]
> +/**
> + * 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) {
s/>=/>/