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Commit 81c9d43f authored by Feng Tang's avatar Feng Tang Committed by Linus Torvalds
Browse files

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: default avatarFeng Tang <feng.tang@intel.com>
Suggested-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Acked-by: default avatarSteven 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d999bd93

Documentation/sysctl/kernel.txt

+17 −0
Original line number Diff line number Diff line
@@ -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

include/linux/kernel.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

include/uapi/linux/sysctl.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

};

kernel/panic.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

kernel/sysctl.c

+7 −0
Original line number Diff line number Diff line
@@ -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",