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x86: make clockevents more robust

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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>
This commit is contained in:
Ingo Molnar
2008-01-30 13:30:03 +01:00
parent 1a0c009ac5
commit 45fe4fe191
1 changed files with 13 additions and 0 deletions
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13
kernel/time/clockevents.c
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@@ -41,6 +41,11 @@ unsigned long clockevent_delta2ns(unsigned long latch,
{ {
u64 clc = ((u64) latch << evt->shift); u64 clc = ((u64) latch << evt->shift);
if (unlikely(!evt->mult)) {
evt->mult = 1;
WARN_ON(1);
}
do_div(clc, evt->mult); do_div(clc, evt->mult);
if (clc < 1000) if (clc < 1000)
clc = 1000; clc = 1000;
@@ -151,6 +156,14 @@ static void clockevents_notify_released(void)
void clockevents_register_device(struct clock_event_device *dev) void clockevents_register_device(struct clock_event_device *dev)
{ {
BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED); 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); spin_lock(&clockevents_lock);