tick/common: Touch watchdog in tick_unfreeze() on all CPUs

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

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 59225b484e4ee00e12d61411a9120a4b68502da8..7e5d3524e924da2a39a0296311a890bc3a7ad3fd 100644 (file)
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -11,6 +11,7 @@
 #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>
@@ -558,6 +559,7 @@ void tick_unfreeze(void)
                trace_suspend_resume(TPS("timekeeping_freeze"),
                                     smp_processor_id(), false);
        } else {
+               touch_softlockup_watchdog();
                tick_resume_local();
        }