From a79017660ea4597ec489fab3b5aaf71dd776dfc7 Mon Sep 17 00:00:00 2001
From: Karsten Wiese <fzu@wemgehoertderstaat.de>
Date: Tue, 4 Mar 2008 14:59:55 -0800
Subject: [PATCH] time: don't touch an offlined CPU's ts->tick_stopped in
 tick_cancel_sched_timer()

Silences WARN_ONs in rcu_enter_nohz() and rcu_exit_nohz(), which appeared
before caused by (repeated) calls to:
        $ echo 0 > /sys/devices/system/cpu/cpu1/online
        $ echo 1 > /sys/devices/system/cpu/cpu1/online

Signed-off-by: Karsten Wiese <fzu@wemgehoertderstaat.de>
Cc: johnstul@us.ibm.com
Cc: Rafael Wysocki <rjw@sisk.pl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/tick-sched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2968298f8f36..686da821d376 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -640,7 +640,7 @@ void tick_cancel_sched_timer(int cpu)
 
 	if (ts->sched_timer.base)
 		hrtimer_cancel(&ts->sched_timer);
-	ts->tick_stopped = 0;
+
 	ts->nohz_mode = NOHZ_MODE_INACTIVE;
 }
 #endif /* HIGH_RES_TIMERS */
-- 
2.20.1