rtc: limit frequency

Due to the hrtimer self rearming mode a user can DoS the machine simply
because it's starved by hrtimer events.

The RTC hrtimer is self rearming.  We really need to limit the frequency
to something sensible.

Signed-off-by: Thomas Gleixner <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ben Greear <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Thomas Gleixner 2011-07-26 16:08:19 -07:00 • committed by Linus Torvalds
commit 431e2bcc37

View file

@ -688,7 +688,7 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
int err = 0;
unsigned long flags;
if (freq <= 0)
if (freq <= 0 || freq > 5000)
return -EINVAL;
spin_lock_irqsave(&rtc->irq_task_lock, flags);