| From 431e2bcc371016824f419baa745f82388258f3ee Mon Sep 17 00:00:00 2001 |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Tue, 26 Jul 2011 16:08:19 -0700 |
| Subject: rtc: limit frequency |
| |
| From: Thomas Gleixner <tglx@linutronix.de> |
| |
| commit 431e2bcc371016824f419baa745f82388258f3ee upstream. |
| |
| 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 <tglx@linutronix.de> |
| Cc: John Stultz <john.stultz@linaro.org> |
| Cc: Ingo Molnar <mingo@elte.hu> |
| Cc: Ben Greear <greearb@candelatech.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| drivers/rtc/interface.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/drivers/rtc/interface.c |
| +++ b/drivers/rtc/interface.c |
| @@ -708,7 +708,7 @@ int rtc_irq_set_freq(struct rtc_device * |
| int err = 0; |
| unsigned long flags; |
| |
| - if (freq <= 0) |
| + if (freq <= 0 || freq > 5000) |
| return -EINVAL; |
| retry: |
| spin_lock_irqsave(&rtc->irq_task_lock, flags); |
