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| author | Li Zhe <lizhe.67@bytedance.com> | 2023-11-23 16:40:22 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-12-10 17:21:44 -0800 |
| commit | 9d02330abd3ecdacc43fc6b16a5668e7e94b7562 (patch) | |
| tree | 019f798651b2d5a714eacf0b0fa3c290324b389f /kernel/watchdog.c | |
| parent | b3ba234171cd0d58df0a13c262210ff8b5fd2830 (diff) | |
| download | linux-9d02330abd3ecdacc43fc6b16a5668e7e94b7562.tar.gz linux-9d02330abd3ecdacc43fc6b16a5668e7e94b7562.tar.bz2 linux-9d02330abd3ecdacc43fc6b16a5668e7e94b7562.zip | |
softlockup: serialized softlockup's log
If multiple CPUs trigger softlockup at the same time with
'softlockup_all_cpu_backtrace=0', the softlockup's logs will appear
staggeredly in dmesg, which will affect the viewing of the logs for
developer. Since the code path for outputting softlockup logs is not a
kernel hotspot and the performance requirements for the code are not
strict, locks are used to serialize the softlockup log output to improve
the readability of the logs.
Link: https://lkml.kernel.org/r/20231123084022.10302-1-lizhe.67@bytedance.com
Signed-off-by: Li Zhe <lizhe.67@bytedance.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Cc: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel/watchdog.c')
| -rw-r--r-- | kernel/watchdog.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 5cd6d4e26915..bf30a6fac665 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -448,6 +448,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) struct pt_regs *regs = get_irq_regs(); int duration; int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace; + static DEFINE_SPINLOCK(watchdog_output_lock); if (!watchdog_enabled) return HRTIMER_NORESTART; @@ -514,6 +515,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) /* Start period for the next softlockup warning. */ update_report_ts(); + spin_lock(&watchdog_output_lock); pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", smp_processor_id(), duration, current->comm, task_pid_nr(current)); @@ -523,6 +525,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) show_regs(regs); else dump_stack(); + spin_unlock(&watchdog_output_lock); if (softlockup_all_cpu_backtrace) { trigger_allbutcpu_cpu_backtrace(smp_processor_id()); |