Commit-ID: 57ccdf449f962ab5fc8cbf26479402f13bdb8be7
Gitweb: http://git.kernel.org/tip/57ccdf449f962ab5fc8cbf26479402f13bdb8be7
Author: Wanpeng Li <wanpeng...@hotmail.com>
AuthorDate: Wed, 7 Sep 2016 18:51:13 +0800
Committer: Thomas Gleixner <t...@linutronix.de>
CommitDate: Tue, 13 Sep 2016 17:53:52 +0200
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...@hotmail.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Link:
http://lkml.kernel.org/r/1473245473-4463-1-git-send-email-wanpeng...@hotmail.com
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
kernel/time/tick-sched.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2ec7c00..3bcb61b 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());
