Commit 84ea7fe3 authored May 12, 2014 by Viresh Kumar Committed by Thomas Gleixner May 12, 2014

hrtimer: Set expiry time before switch_hrtimer_base()



switch_hrtimer_base() calls hrtimer_check_target() which ensures that
we do not migrate a timer to a remote cpu if the timer expires before
the current programmed expiry time on that remote cpu.

But __hrtimer_start_range_ns() calls switch_hrtimer_base() before the
new expiry time is set. So the sanity check in hrtimer_check_target()
is operating on stale or even uninitialized data.

Update expiry time before calling switch_hrtimer_base().

[ tglx: Rewrote changelog once again ]

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: linaro-networking@linaro.org
Cc: fweisbec@gmail.com
Cc: arvind.chauhan@arm.com
Link: http://lkml.kernel.org/r/81999e148745fc51bbcd0615823fbab9b2e87e23.1399882253.git.viresh.kumar@linaro.org


Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent d6d211db

kernel/hrtimer.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -990,11 +990,8 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
		/* Remove an active timer from the queue: */
		ret = remove_hrtimer(timer, base);

		/* Switch the timer base, if necessary: */
		new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);

		if (mode & HRTIMER_MODE_REL) {
		tim = ktime_add_safe(tim, new_base->get_time());
		tim = ktime_add_safe(tim, base->get_time());
		/*
		* CONFIG_TIME_LOW_RES is a temporary way for architectures
		* to signal that they simply return xtime in
		@@ -1009,6 +1006,9 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,

		hrtimer_set_expires_range_ns(timer, tim, delta_ns);

		/* Switch the timer base, if necessary: */
		new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);

		timer_stats_hrtimer_set_start_info(timer);

		leftmost = enqueue_hrtimer(timer, new_base);