Messages in this thread | | | Date | Thu, 2 Mar 2006 10:43:12 -0600 | From | "Ram Gupta" <> | Subject | Re: [PATCH] fix potential jiffies overflow |
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On 3/2/06, Atsushi Nemoto <anemo@mba.ocn.ne.jp> wrote: > I found i386 timer_resume is updating jiffies, not jiffies_64. It > looks there is a potential overflow problem. Is this a correct fix? > > Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> > > diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c > index a14d594..e4ed172 100644 > --- a/arch/i386/kernel/time.c > +++ b/arch/i386/kernel/time.c > @@ -413,7 +413,7 @@ static int timer_resume(struct sys_devic > xtime.tv_sec = sec; > xtime.tv_nsec = 0; > write_sequnlock_irqrestore(&xtime_lock, flags); > - jiffies += sleep_length; > + jiffies_64 += sleep_length; > wall_jiffies += sleep_length; > if (last_timer->resume) > last_timer->resume();
The 64-bit jiffies value is not atomic. You need to hold xtime_lock to read it. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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