Commit d7b41a24 authored Apr 26, 2008 by Bodo Stroesser Committed by Thomas Gleixner Apr 27, 2008

hrtimer: timeout too long when using HRTIMER_CB_SOFTIRQ



When using hrtimer with timer->cb_mode == HRTIMER_CB_SOFTIRQ
in some cases the clockevent is not programmed.
This happens, if:
 - a timer is rearmed while it's state is HRTIMER_STATE_CALLBACK
 - hrtimer_reprogram() returns -ETIME, when it is called after
   CALLBACK is finished. This occurs if the new timer->expires
   is in the past when CALLBACK is done.
In this case, the timer needs to be removed from the tree and put
onto the pending list again.

The patch is against 2.6.22.5, but AFAICS, it is relevant
for 2.6.25 also (in run_hrtimer_pending()).

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent c3bf9bc2

kernel/hrtimer.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -1080,8 +1080,19 @@ static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base)
		* If the timer was rearmed on another CPU, reprogram
		* the event device.
		*/
		if (timer->base->first == &timer->node)
		hrtimer_reprogram(timer, timer->base);
		struct hrtimer_clock_base *base = timer->base;

		if (base->first == &timer->node &&
		hrtimer_reprogram(timer, base)) {
		/*
		* Timer is expired. Thus move it from tree to
		* pending list again.
		*/
		__remove_hrtimer(timer, base,
		HRTIMER_STATE_PENDING, 0);
		list_add_tail(&timer->cb_entry,
		&base->cpu_base->cb_pending);
		}
		}
		}
		spin_unlock_irq(&cpu_base->lock);

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