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authorOleg Nesterov <oleg@redhat.com>2015-06-11 14:46:44 +0200
committerThomas Gleixner <tglx@linutronix.de>2015-06-19 00:09:56 +0200
commitc04dca02bc73096435a5c36efd5ccb2171edcbe1 (patch)
tree6875551d63882ac926b68a964c9629f45d0c4f7d /kernel/time
parentselftest: Timers: Avoid signal deadlock in leap-a-day (diff)
downloadlinux-c04dca02bc73096435a5c36efd5ccb2171edcbe1.tar.xz
linux-c04dca02bc73096435a5c36efd5ccb2171edcbe1.zip
hrtimer: Remove HRTIMER_STATE_MIGRATE
I do not understand HRTIMER_STATE_MIGRATE. Unless I am totally confused it looks buggy and simply unneeded. migrate_hrtimer_list() sets it to keep hrtimer_active() == T, but this is not enough: this can fool, say, hrtimer_is_queued() in dequeue_signal(). Can't migrate_hrtimer_list() simply use HRTIMER_STATE_ENQUEUED? This fixes the race and we can kill STATE_MIGRATE. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124743.072387650@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/hrtimer.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 278d4b36fd94..b1b795e5e0b1 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1508,11 +1508,11 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
debug_deactivate(timer);
/*
- * Mark it as STATE_MIGRATE not INACTIVE otherwise the
+ * Mark it as ENQUEUED not INACTIVE otherwise the
* timer could be seen as !active and just vanish away
* under us on another CPU
*/
- __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
+ __remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);
timer->base = new_base;
/*
* Enqueue the timers on the new cpu. This does not
@@ -1523,9 +1523,6 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
* event device.
*/
enqueue_hrtimer(timer, new_base);
-
- /* Clear the migration state bit */
- timer->state &= ~HRTIMER_STATE_MIGRATE;
}
}