diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2021-11-07 14:51:16 +1000 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2021-11-10 16:12:00 +0100 |
| commit | 5d5e4522a7f404d1a96fd6c703989d32a9c9568d (patch) | |
| tree | f0241bc19c8cc4106ac4d2dff236cd58528ef0e4 /include | |
| parent | 26d1982fd17c2cac77f9cf764255362ccb28fe49 (diff) | |
printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces
printk from NMI context relies on irq work being raised on the local CPU
to print to console. This can be a problem if the NMI was raised by a
lockup detector to print lockup stack and regs, because the CPU may not
enable irqs (because it is locked up).
Introduce printk_trigger_flush() that can be called another CPU to try
to get those messages to the console, call that where printk_safe_flush
was previously called.
Fixes: 93d102f094be ("printk: remove safe buffers")
Cc: stable@vger.kernel.org # 5.15
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20211107045116.1754411-1-npiggin@gmail.com
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/printk.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/printk.h b/include/linux/printk.h index a1379df43251..596ad6fa0336 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -206,6 +206,7 @@ void dump_stack_print_info(const char *log_lvl); void show_regs_print_info(const char *log_lvl); extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold; extern asmlinkage void dump_stack(void) __cold; +void printk_trigger_flush(void); #else static inline __printf(1, 0) int vprintk(const char *s, va_list args) @@ -282,6 +283,9 @@ static inline void dump_stack_lvl(const char *log_lvl) static inline void dump_stack(void) { } +static inline void printk_trigger_flush(void) +{ +} #endif #ifdef CONFIG_SMP |