From 81c9d43f94870be66146739c6e61df40dc17bb64 Mon Sep 17 00:00:00 2001
From: Feng Tang <feng.tang@intel.com>
Date: Thu, 3 Jan 2019 15:28:20 -0800
Subject: [PATCH] kernel/sysctl: add panic_print into sysctl
So that we can also runtime chose to print out the needed system info
for panic, other than setting the kernel cmdline.
Link: http://lkml.kernel.org/r/1543398842-19295-3-git-send-email-feng.tang@intel.com
Signed-off-by: Feng Tang <feng.tang@intel.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Documentation/sysctl/kernel.txt | 17 +++++++++++++++++
include/linux/kernel.h | 1 +
include/uapi/linux/sysctl.h | 1 +
kernel/panic.c | 2 +-
kernel/sysctl.c | 7 +++++++
kernel/sysctl_binary.c | 1 +
6 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 1b8775298cf7a..c0527d8a468a1 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -60,6 +60,7 @@ show up in /proc/sys/kernel:
- panic_on_stackoverflow
- panic_on_unrecovered_nmi
- panic_on_warn
+- panic_print
- panic_on_rcu_stall
- perf_cpu_time_max_percent
- perf_event_paranoid
@@ -654,6 +655,22 @@ a kernel rebuild when attempting to kdump at the location of a WARN().
==============================================================
+panic_print:
+
+Bitmask for printing system info when panic happens. User can chose
+combination of the following bits:
+
+bit 0: print all tasks info
+bit 1: print system memory info
+bit 2: print timer info
+bit 3: print locks info if CONFIG_LOCKDEP is on
+bit 4: print ftrace buffer
+
+So for example to print tasks and memory info on panic, user can:
+ echo 3 > /proc/sys/kernel/panic_print
+
+==============================================================
+
panic_on_rcu_stall:
When set to 1, calls panic() after RCU stall detection messages. This
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index d6aac75b51baa..8f0e68e250a76 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -527,6 +527,7 @@ static inline u32 int_sqrt64(u64 x)
extern void bust_spinlocks(int yes);
extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
extern int panic_timeout;
+extern unsigned long panic_print;
extern int panic_on_oops;
extern int panic_on_unrecovered_nmi;
extern int panic_on_io_nmi;
diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
index d71013fffaf65..87aa2a6d91256 100644
--- a/include/uapi/linux/sysctl.h
+++ b/include/uapi/linux/sysctl.h
@@ -153,6 +153,7 @@ enum
KERN_NMI_WATCHDOG=75, /* int: enable/disable nmi watchdog */
KERN_PANIC_ON_NMI=76, /* int: whether we will panic on an unrecovered */
KERN_PANIC_ON_WARN=77, /* int: call panic() in WARN() functions */
+ KERN_PANIC_PRINT=78, /* ulong: bitmask to print system info on panic */
};
diff --git a/kernel/panic.c b/kernel/panic.c
index 855f66738bc7b..f121e6ba7e114 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -51,7 +51,7 @@ EXPORT_SYMBOL_GPL(panic_timeout);
#define PANIC_PRINT_TIMER_INFO 0x00000004
#define PANIC_PRINT_LOCK_INFO 0x00000008
#define PANIC_PRINT_FTRACE_INFO 0x00000010
-static unsigned long panic_print;
+unsigned long panic_print;
ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 7f6c1a3b3485f..ba4d9e85feb8c 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -807,6 +807,13 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
+ {
+ .procname = "panic_print",
+ .data = &panic_print,
+ .maxlen = sizeof(unsigned long),
+ .mode = 0644,
+ .proc_handler = proc_doulongvec_minmax,
+ },
#if defined CONFIG_PRINTK
{
.procname = "printk",
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 07148b4974516..73c132095a7bd 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -140,6 +140,7 @@ static const struct bin_table bin_kern_table[] = {
{ CTL_INT, KERN_MAX_LOCK_DEPTH, "max_lock_depth" },
{ CTL_INT, KERN_PANIC_ON_NMI, "panic_on_unrecovered_nmi" },
{ CTL_INT, KERN_PANIC_ON_WARN, "panic_on_warn" },
+ { CTL_ULONG, KERN_PANIC_PRINT, "panic_print" },
{}
};
--
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