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Commit d4496b39 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

clockevents: prevent endless loop in periodic broadcast handler 



The reprogramming of the periodic broadcast handler was broken,
when the first programming returned -ETIME. The clockevents code
stores the new expiry value in the clock events device next_event field
only when the programming time has not been elapsed yet. The loop in
question calculates the new expiry value from the next_event value
and therefor never increases.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7c1e7689

kernel/time/tick-broadcast.c

+8 −3
Original line number Original line Diff line number Diff line
@@ -175,6 +175,8 @@ static void tick_do_periodic_broadcast(void) 
 */

 */

static void tick_handle_periodic_broadcast(struct clock_event_device *dev)

static void tick_handle_periodic_broadcast(struct clock_event_device *dev)

{

{

	ktime_t next;



	tick_do_periodic_broadcast();

	tick_do_periodic_broadcast();





	/*

	/*
@@ -185,10 +187,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev) 




	/*

	/*

	 * Setup the next period for devices, which do not have

	 * Setup the next period for devices, which do not have

	 * periodic mode:

	 * periodic mode. We read dev->next_event first and add to it

	 * when the event alrady expired. clockevents_program_event()

	 * sets dev->next_event only when the event is really

	 * programmed to the device.

	 */

	 */

	for (;;) {

	for (next = dev->next_event; ;) {

		ktime_t next = ktime_add(dev->next_event, tick_period);

		next = ktime_add(next, tick_period);





		if (!clockevents_program_event(dev, next, ktime_get()))

		if (!clockevents_program_event(dev, next, ktime_get()))

			return;

			return;