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 /arch/powerpc/kernel/watchdog.c | |
| 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 'arch/powerpc/kernel/watchdog.c')
| -rw-r--r-- | arch/powerpc/kernel/watchdog.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index dc17d8903d4f..6b7a83d5e03e 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -186,6 +186,12 @@ static void watchdog_smp_panic(int cpu, u64 tb) if (sysctl_hardlockup_all_cpu_backtrace) trigger_allbutself_cpu_backtrace(); + /* + * Force flush any remote buffers that might be stuck in IRQ context + * and therefore could not run their irq_work. + */ + printk_trigger_flush(); + if (hardlockup_panic) nmi_panic(NULL, "Hard LOCKUP"); |