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authorThomas Gleixner <tglx@linutronix.de>2015-07-05 20:53:17 +0000
committerThomas Gleixner <tglx@linutronix.de>2015-07-07 18:46:48 +0200
commitc4288334818c81c946acb23d2319881f58c3d497 (patch)
tree77b3e765201a4d673d130e169becc0211f69f161
parentd5113e13a550bc9c2b53cc9944b8a06453c4a0a1 (diff)
downloadop-kernel-dev-c4288334818c81c946acb23d2319881f58c3d497.zip
op-kernel-dev-c4288334818c81c946acb23d2319881f58c3d497.tar.gz
tick/broadcast: Handle spurious interrupts gracefully
Andriy reported that on a virtual machine the warning about negative expiry time in the clock events programming code triggered: hpet: hpet0 irq 40 for MSI hpet: hpet1 irq 41 for MSI Switching to clocksource hpet WARNING: at kernel/time/clockevents.c:239 [<ffffffff810ce6eb>] clockevents_program_event+0xdb/0xf0 [<ffffffff810cf211>] tick_handle_periodic_broadcast+0x41/0x50 [<ffffffff81016525>] timer_interrupt+0x15/0x20 When the second hpet is installed as a per cpu timer the broadcast event is not longer required and stopped, which sets the next_evt of the broadcast device to KTIME_MAX. If after that a spurious interrupt happens on the broadcast device, then the current code blindly handles it and tries to reprogram the broadcast device afterwards, which adds the period to next_evt. KTIME_MAX + period results in a negative expiry value causing the WARN_ON in the clockevents code to trigger. Add a proper check for the state of the broadcast device into the interrupt handler and return if the interrupt is spurious. [ Folded in pointer fix from Sudeep ] Reported-by: Andriy Gapon <avg@FreeBSD.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20150705205221.802094647@linutronix.de
-rw-r--r--kernel/time/tick-broadcast.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index c8d731a..ee3cf94 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -316,6 +316,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
bool bc_local;
raw_spin_lock(&tick_broadcast_lock);
+
+ /* Handle spurious interrupts gracefully */
+ if (clockevent_state_shutdown(tick_broadcast_device.evtdev)) {
+ raw_spin_unlock(&tick_broadcast_lock);
+ return;
+ }
+
bc_local = tick_do_periodic_broadcast();
if (clockevent_state_oneshot(dev)) {
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