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authorWanpeng Li <wanpeng.li@hotmail.com>2016-09-07 18:51:13 +0800
committerThomas Gleixner <tglx@linutronix.de>2016-09-13 17:53:52 +0200
commit57ccdf449f962ab5fc8cbf26479402f13bdb8be7 (patch)
tree89cd6859175a3aa2503903af7d11813e2edabddb /kernel/time/tick-sched.c
parent2ea3401e2a84eed3f5f55b2075706f88df160d85 (diff)
tick/nohz: Prevent stopping the tick on an offline CPU
can_stop_full_tick() has no check for offline cpus. So it allows to stop the tick on an offline cpu from the interrupt return path, which is wrong and subsequently makes irq_work_needs_cpu() warn about being called for an offline cpu. Commit f7ea0fd639c2c4 ("tick: Don't invoke tick_nohz_stop_sched_tick() if the cpu is offline") added prevention for can_stop_idle_tick(), but forgot to do the same in can_stop_full_tick(). Add it. [ tglx: Massaged changelog ] Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1473245473-4463-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time/tick-sched.c')
-rw-r--r--kernel/time/tick-sched.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2ec7c00228f3..3bcb61b52f6c 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -186,10 +186,13 @@ static bool check_tick_dependency(atomic_t *dep)
return false;
}
-static bool can_stop_full_tick(struct tick_sched *ts)
+static bool can_stop_full_tick(int cpu, struct tick_sched *ts)
{
WARN_ON_ONCE(!irqs_disabled());
+ if (unlikely(!cpu_online(cpu)))
+ return false;
+
if (check_tick_dependency(&tick_dep_mask))
return false;
@@ -843,7 +846,7 @@ static void tick_nohz_full_update_tick(struct tick_sched *ts)
if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE)
return;
- if (can_stop_full_tick(ts))
+ if (can_stop_full_tick(cpu, ts))
tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
else if (ts->tick_stopped)
tick_nohz_restart_sched_tick(ts, ktime_get());