From: Chunyan Zhang <zhang.lyra@gmail.com>
Date: Fri, 10 Jan 2020 08:39:02 +0000 (+0800)
Subject: tick/common: Touch watchdog in tick_unfreeze() on all CPUs
X-Git-Tag: v5.6-rc1~177^2~8
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=5167c506d62dd9ffab73eba23c79b0a8845c9fe1;p=linux.git

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 59225b484e4e..7e5d3524e924 100644
--- 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();
 	}