diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2015-06-11 14:46:45 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-06-19 00:09:56 +0200 |
| commit | 8edfb0362e8e52dec2de08fa163af01c9da2c9d0 (patch) | |
| tree | 5f607cf35b8c625695eb7cc3d357432f733185fa | |
| parent | c04dca02bc73096435a5c36efd5ccb2171edcbe1 (diff) | |
hrtimer: Fix hrtimer_is_queued() hole
A queued hrtimer that gets restarted (hrtimer_start*() while
hrtimer_is_queued()) will briefly appear as unqueued/inactive, even
though the timer has always been active, we just moved it.
Close this hole by preserving timer->state in
hrtimer_start_range_ns()'s remove_hrtimer() call.
Reported-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/20150611124743.175989138@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | kernel/time/hrtimer.c | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index b1b795e5e0b1..1604157374d7 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -889,10 +889,10 @@ static void __remove_hrtimer(struct hrtimer *timer, * remove hrtimer, called with base lock held */ static inline int -remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) +remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base, bool restart) { if (hrtimer_is_queued(timer)) { - unsigned long state; + unsigned long state = timer->state; int reprogram; /* @@ -906,12 +906,15 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) debug_deactivate(timer); timer_stats_hrtimer_clear_start_info(timer); reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases); - /* - * We must preserve the CALLBACK state flag here, - * otherwise we could move the timer base in - * switch_hrtimer_base. - */ - state = timer->state & HRTIMER_STATE_CALLBACK; + + if (!restart) { + /* + * We must preserve the CALLBACK state flag here, + * otherwise we could move the timer base in + * switch_hrtimer_base. + */ + state &= HRTIMER_STATE_CALLBACK; + } __remove_hrtimer(timer, base, state, reprogram); return 1; } @@ -936,7 +939,7 @@ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, base = lock_hrtimer_base(timer, &flags); /* Remove an active timer from the queue: */ - remove_hrtimer(timer, base); + remove_hrtimer(timer, base, true); if (mode & HRTIMER_MODE_REL) { tim = ktime_add_safe(tim, base->get_time()); @@ -1005,7 +1008,7 @@ int hrtimer_try_to_cancel(struct hrtimer *timer) base = lock_hrtimer_base(timer, &flags); if (!hrtimer_callback_running(timer)) - ret = remove_hrtimer(timer, base); + ret = remove_hrtimer(timer, base, false); unlock_hrtimer_base(timer, &flags); |