The patch titled
Subject: watchdog: explicitly update timestamp when reporting softlockup
has been removed from the -mm tree. Its filename was
watchdog-explicitly-update-timestamp-when-reporting-softlockup.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Petr Mladek <pmladek@xxxxxxxx>
Subject: watchdog: explicitly update timestamp when reporting softlockup
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@xxxxxxxx
Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Laurence Oberman <loberman@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/watchdog.c | 3 +++
1 file changed, 3 insertions(+)
--- a/kernel/watchdog.c~watchdog-explicitly-update-timestamp-when-reporting-softlockup
+++ a/kernel/watchdog.c
@@ -410,6 +410,9 @@ static enum hrtimer_restart watchdog_tim
}
}
+ /* 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));
_
Patches currently in -mm which might be from pmladek@xxxxxxxx are
