Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.11 109/329] watchdog: explicitly update timestamp when reporting softlockup | Date | Mon, 17 May 2021 16:00:20 +0200 |
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From: Petr Mladek <pmladek@suse.com>
[ Upstream commit c9ad17c991492f4390f42598f6ab0531f87eed07 ]
The softlockup situation might stay for a long time or even forever. When it happens, the softlockup debug messages are printed in regular intervals defined by get_softlockup_thresh().
There is a mystery. The repeated message is printed after the full interval that is defined by get_softlockup_thresh(). But the timer callback is called more often as defined by sample_period. The code looks like the soflockup should get reported in every sample_period when it was once behind the thresh.
It works only by chance. The watchdog is touched when printing the stall report, for example, in printk_stack_address().
Make the behavior clear and predictable by explicitly updating the timestamp in watchdog_timer_fn() when the report gets printed.
Link: https://lkml.kernel.org/r/20210311122130.6788-3-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Laurence Oberman <loberman@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- kernel/watchdog.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index c58244064de8..7776d53a015c 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -409,6 +409,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) } } + /* Start period for the next softlockup warning. */ + update_touch_ts(); + pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", smp_processor_id(), duration, current->comm, task_pid_nr(current)); -- 2.30.2
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