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authorThomas Gleixner <tglx@linutronix.de>2009-07-19 17:09:12 +0200
committerThomas Gleixner <tglx@linutronix.de>2009-07-19 17:15:54 +0200
commit79ef2bb01445400def20c7993b27fbcad27ca95f (patch)
tree2b4941a2b4a6822dd0f50f13ff04e9e0a369878e
parent4841158b26e28e1476eed84c7347c18f11317750 (diff)
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clocksource: Prevent NULL pointer dereference
Writing a zero length string to sys/.../current_clocksource will cause a NULL pointer dereference if the clock events system is in one shot (highres or nohz) mode. Pointed-out-by: Dan Carpenter <error27@gmail.com> LKML-Reference: <alpine.DEB.2.00.0907191545580.12306@bicker> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--kernel/time/clocksource.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 592bf58..7466cb8 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -513,7 +513,7 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev,
* Check to make sure we don't switch to a non-highres capable
* clocksource if the tick code is in oneshot mode (highres or nohz)
*/
- if (tick_oneshot_mode_active() &&
+ if (tick_oneshot_mode_active() && ovr &&
!(ovr->flags & CLOCK_SOURCE_VALID_FOR_HRES)) {
printk(KERN_WARNING "%s clocksource is not HRT compatible. "
"Cannot switch while in HRT/NOHZ mode\n", ovr->name);