Messages in this thread Patch in this message | | | From | lizhe.67@bytedanc ... | Subject | [RFC] softlockup: serialized softlockup's log | Date | Tue, 14 Nov 2023 10:15:29 +0800 |
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From: Li Zhe <lizhe.67@bytedance.com>
If multiple CPUs trigger softlockup at the same time, 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.
Signed-off-by: Li Zhe <lizhe.67@bytedance.com> --- kernel/watchdog.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 5cd6d4e26915..8324ac194d0a 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_timer_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_timer_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_timer_lock); if (softlockup_all_cpu_backtrace) { trigger_allbutcpu_cpu_backtrace(smp_processor_id()); -- 2.20.1
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