From: Thomas Gleixner Date: Wed, 3 Sep 2008 21:36:57 +0000 (+0000) Subject: clockevents: prevent endless loop in periodic broadcast handler X-Git-Tag: v2.6.27-rc6~24^2~10 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d4496b39559c6d43f83e4c08b899984f8b8089b5;p=linux-2.6 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: Thomas Gleixner Signed-off-by: Ingo Molnar --- diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 31463d370b..3044a88357 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -175,6 +175,8 @@ static void tick_do_periodic_broadcast(void) */ static void tick_handle_periodic_broadcast(struct clock_event_device *dev) { + ktime_t next; + 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 - * 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 (;;) { - ktime_t next = ktime_add(dev->next_event, tick_period); + for (next = dev->next_event; ;) { + next = ktime_add(next, tick_period); if (!clockevents_program_event(dev, next, ktime_get())) return;