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authorIngo Molnar2008-01-30 13:30:03 +0100
committerIngo Molnar2008-01-30 13:30:03 +0100
commit45fe4fe19120a22f7339f5bb110447170c25fca9 (patch)
tree06639135ca5bc60e952670dd7df40e195edb2ad9 /kernel/time
parent1a0c009ac53de4a7664a1239936f0bc258133156 (diff)
x86: make clockevents more robust
detect zero event-device multiplicators - they then cause division-by-zero crashes if a clockevent has been initialized incorrectly. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/clockevents.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 5fb139fef9fa..3e59fce6dd43 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -41,6 +41,11 @@ unsigned long clockevent_delta2ns(unsigned long latch,
{
u64 clc = ((u64) latch << evt->shift);
+ if (unlikely(!evt->mult)) {
+ evt->mult = 1;
+ WARN_ON(1);
+ }
+
do_div(clc, evt->mult);
if (clc < 1000)
clc = 1000;
@@ -151,6 +156,14 @@ static void clockevents_notify_released(void)
void clockevents_register_device(struct clock_event_device *dev)
{
BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
+ /*
+ * A nsec2cyc multiplicator of 0 is invalid and we'd crash
+ * on it, so fix it up and emit a warning:
+ */
+ if (unlikely(!dev->mult)) {
+ dev->mult = 1;
+ WARN_ON(1);
+ }
spin_lock(&clockevents_lock);