Messages in this thread Patch in this message | | | From | Petr Mladek <> | Subject | [PATCH v2 2/7] watchdog: Explicitly update timestamp when reporting softlockup | Date | Thu, 11 Mar 2021 13:21:25 +0100 |
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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.
Signed-off-by: Petr Mladek <pmladek@suse.com> --- 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)); -- 2.26.2
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