From: Chunyan Zhang zhang.lyra@gmail.com
commit 5167c506d62dd9ffab73eba23c79b0a8845c9fe1 upstream.
Suspend to IDLE invokes tick_unfreeze() on resume. tick_unfreeze() on the first resuming CPU resumes timekeeping, which also has the side effect of resetting the softlockup watchdog on this CPU.
But on the secondary CPUs the watchdog is not reset in the resume / unfreeze() path, which can result in false softlockup warnings on those CPUs depending on the time spent in suspend.
Prevent this by clearing the softlock watchdog in the unfreeze path also on the secondary resuming CPUs.
[ tglx: Massaged changelog ]
Signed-off-by: Chunyan Zhang chunyan.zhang@unisoc.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Link: https://lore.kernel.org/r/20200110083902.27276-1-chunyan.zhang@unisoc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/time/tick-common.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -15,6 +15,7 @@ #include <linux/err.h> #include <linux/hrtimer.h> #include <linux/interrupt.h> +#include <linux/nmi.h> #include <linux/percpu.h> #include <linux/profile.h> #include <linux/sched.h> @@ -520,6 +521,7 @@ void tick_unfreeze(void) trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), false); } else { + touch_softlockup_watchdog(); tick_resume_local(); }