Subject: [PATCH V6 16/16] rv/reactor: Add the panic reactor

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

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

diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index f1d92d431130..ce2a90a89f55 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -71,3 +71,11 @@ config RV_REACT_PRINTK
help
Enables the printk reactor. The printk reactor emits a printk()
message if an exception is found.
+
+config RV_REACT_PANIC
+ bool "Panic reactor"
+ depends on RV_REACTORS
+ default y
+ help
+ Enables the panic reactor. The panic reactor emits a printk()
+ message if an exception is found and panic()s the system.
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index a13c750a35c1..963d14875b45 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_RV_MON_WIP) += monitors/wip/wip.o
obj-$(CONFIG_RV_MON_WWNR) += monitors/wwnr/wwnr.o
obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
+obj-$(CONFIG_RV_REACT_PANIC) += reactor_panic.o
diff --git a/kernel/trace/rv/reactor_panic.c b/kernel/trace/rv/reactor_panic.c
new file mode 100644
index 000000000000..e9757db801f3
--- /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


2022-07-21 16:01:31

by Steven Rostedt

[permalink] [raw]
Subject: Re: [PATCH V6 16/16] rv/reactor: Add the panic reactor

On Tue, 19 Jul 2022 19:27:21 +0200
Daniel Bristot de Oliveira <[email protected]> wrote:

> 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.

BTW, do you plan on adding models to model the reactors?

;-)

-- Steve

Subject: Re: [PATCH V6 16/16] rv/reactor: Add the panic reactor

On 7/21/22 17:31, Steven Rostedt wrote:
> On Tue, 19 Jul 2022 19:27:21 +0200
> Daniel Bristot de Oliveira <[email protected]> wrote:
>
>> 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.
>
> BTW, do you plan on adding models to model the reactors?

I was about to say that at the panic level, it would not be needed, as code inspection
is reasonable (people in Elisa did IIRC). But then I recalled that we
have a printk reactor, and one might model it - at event level :-)

But then can disable the reactor :-).

-- Daniel

> ;-)
>
> -- Steve