From: Petr Mladek Date: Fri, 30 Apr 2021 05:54:23 +0000 (-0700) Subject: watchdog: explicitly update timestamp when reporting softlockup X-Git-Tag: v5.11.22~221 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cc622029e0a155722b0b48b5396d3947470a6337;p=thirdparty%2Fkernel%2Fstable.git watchdog: explicitly update timestamp when reporting softlockup [ 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 Cc: Ingo Molnar Cc: Laurence Oberman Cc: Michal Hocko Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Whitchurch Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- diff --git a/kernel/watchdog.c b/kernel/watchdog.c index c58244064de83..7776d53a015ce 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));