[V5,16/16] rv/reactor: Add the panic reactor

Commit Message

Daniel Bristot de Oliveira July 13, 2022, 9:17 p.m. UTC

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 <[e-mail]>
Cc: Guenter Roeck <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Marco Elver <[e-mail]>
Cc: Dmitry Vyukov <[e-mail]>
Cc: "Paul E. McKenney" <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: Gabriele Paoloni <[e-mail]>
Cc: Juri Lelli <[e-mail]>
Cc: Clark Williams <[e-mail]>
Cc: Tao Zhou <[e-mail]>
Cc: Randy Dunlap <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Daniel Bristot de Oliveira <[e-mail]>
---
 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

Comments

kernel test robot July 18, 2022, 2:05 a.m. UTC | #1

Hi Daniel,

I love your patch! Perhaps something to improve:

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

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

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


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

kernel test robot July 18, 2022, 11:50 a.m. UTC | #2

Hi Daniel,

I love your patch! Perhaps something to improve:

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

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

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

All warnings (new ones prefixed by >>):

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


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

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

Patch

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