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panic: add options to print system info when panic happens 

Kernel panic issues are always painful to debug, partially because it's
not easy to get enough information of the context when panic happens.

And we have ramoops and kdump for that, while this commit tries to
provide a easier way to show the system info by adding a cmdline
parameter, referring some idea from sysrq handler.

Link: http://lkml.kernel.org/r/1543398842-19295-2-git-send-email-feng.tang@intel.com
Signed-off-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.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: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Feng Tang 2019-01-03 15:28:17 -08:00 committed by Linus Torvalds
parent d187715589
commit d999bd9392
2 changed files with 36 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/admin-guide/kernel-parameters.txt
View File

@ -3092,6 +3092,14 @@
timeout < 0: reboot immediately
Format: <timeout>
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
panic_on_warn panic() instead of WARN(). Useful to cause kdump
on a WARN().

28
kernel/panic.c
View File

@ -46,6 +46,13 @@ int panic_on_warn __read_mostly;
int panic_timeout = CONFIG_PANIC_TIMEOUT;
EXPORT_SYMBOL_GPL(panic_timeout);
#define PANIC_PRINT_TASK_INFO 0x00000001
#define PANIC_PRINT_MEM_INFO 0x00000002
#define PANIC_PRINT_TIMER_INFO 0x00000004
#define PANIC_PRINT_LOCK_INFO 0x00000008
#define PANIC_PRINT_FTRACE_INFO 0x00000010
static unsigned long panic_print;
ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
EXPORT_SYMBOL(panic_notifier_list);
@ -125,6 +132,24 @@ void nmi_panic(struct pt_regs *regs, const char *msg)
}
EXPORT_SYMBOL(nmi_panic);
static void panic_print_sys_info(void)
{
if (panic_print & PANIC_PRINT_TASK_INFO)
show_state();
if (panic_print & PANIC_PRINT_MEM_INFO)
show_mem(0, NULL);
if (panic_print & PANIC_PRINT_TIMER_INFO)
sysrq_timer_list_show();
if (panic_print & PANIC_PRINT_LOCK_INFO)
debug_show_all_locks();
if (panic_print & PANIC_PRINT_FTRACE_INFO)
ftrace_dump(DUMP_ALL);
}
/**
* panic - halt the system
* @fmt: The text string to print
@ -254,6 +279,8 @@ void panic(const char *fmt, ...)
debug_locks_off();
console_flush_on_panic();
panic_print_sys_info();
if (!panic_blink)
panic_blink = no_blink;
@ -658,6 +685,7 @@ void refcount_error_report(struct pt_regs *regs, const char *err)
#endif
core_param(panic, panic_timeout, int, 0644);
core_param(panic_print, panic_print, ulong, 0644);
core_param(pause_on_oops, pause_on_oops, int, 0644);
core_param(panic_on_warn, panic_on_warn, int, 0644);
core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);