diff options
| author | Feng Tang <feng.tang@intel.com> | 2019-05-17 14:31:50 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-18 15:52:26 -0700 |
| commit | de6da1e8bcf0dd2058b950b127491821207679dc (patch) | |
| tree | 2d54c823763d46cd070e5a721040bc1514df52ed /kernel | |
| parent | 5d59aa8f9ce972b472201aed86e904bb75879ff0 (diff) | |
panic: add an option to replay all the printk message in buffer
Currently on panic, kernel will lower the loglevel and print out pending
printk msg only with console_flush_on_panic().
Add an option for users to configure the "panic_print" to replay all
dmesg in buffer, some of which they may have never seen due to the
loglevel setting, which will help panic debugging .
[feng.tang@intel.com: keep the original console_flush_on_panic() inside panic()]
Link: http://lkml.kernel.org/r/1556199137-14163-1-git-send-email-feng.tang@intel.com
[feng.tang@intel.com: use logbuf lock to protect the console log index]
Link: http://lkml.kernel.org/r/1556269868-22654-1-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1556095872-36838-1-git-send-email-feng.tang@intel.com
Signed-off-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/panic.c | 6 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 12 |
2 files changed, 16 insertions, 2 deletions
diff --git a/kernel/panic.c b/kernel/panic.c index 8779d64bace0..b4543a31a495 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -51,6 +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 +#define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 unsigned long panic_print; ATOMIC_NOTIFIER_HEAD(panic_notifier_list); @@ -134,6 +135,9 @@ EXPORT_SYMBOL(nmi_panic); static void panic_print_sys_info(void) { + if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) + console_flush_on_panic(CONSOLE_REPLAY_ALL); + if (panic_print & PANIC_PRINT_TASK_INFO) show_state(); @@ -277,7 +281,7 @@ void panic(const char *fmt, ...) * panic() is not being callled from OOPS. */ debug_locks_off(); - console_flush_on_panic(); + console_flush_on_panic(CONSOLE_FLUSH_PENDING); panic_print_sys_info(); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 17102fd4c136..a6e06fe38e41 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2535,10 +2535,11 @@ void console_unblank(void) /** * console_flush_on_panic - flush console content on panic + * @mode: flush all messages in buffer or just the pending ones * * Immediately output all pending messages no matter what. */ -void console_flush_on_panic(void) +void console_flush_on_panic(enum con_flush_mode mode) { /* * If someone else is holding the console lock, trylock will fail @@ -2549,6 +2550,15 @@ void console_flush_on_panic(void) */ console_trylock(); console_may_schedule = 0; + + if (mode == CONSOLE_REPLAY_ALL) { + unsigned long flags; + + logbuf_lock_irqsave(flags); + console_seq = log_first_seq; + console_idx = log_first_idx; + logbuf_unlock_irqrestore(flags); + } console_unlock(); } |