Messages in this thread Patch in this message | | | Date | Fri, 03 Mar 2006 11:32:46 +0900 (JST) | Subject | Re: [PATCH] fix potential jiffies overflow | From | Atsushi Nemoto <> |
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>>>>> On Thu, 2 Mar 2006 10:43:12 -0600, "Ram Gupta" <ram.gupta5@gmail.com> said: >> I found i386 timer_resume is updating jiffies, not jiffies_64. It >> looks there is a potential overflow problem. Is this a correct >> fix?
ram> The 64-bit jiffies value is not atomic. You need to hold ram> xtime_lock to read it.
OK, and I guess wall_jiffies also needs xtime_lock.
I found i386 timer_resume is updating jiffies, not jiffies_64. It looks there is a potential overflow problem. And jiffies_64 and wall_jiffies should be protected by xtime_lock.
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..9d30747 100644 --- a/arch/i386/kernel/time.c +++ b/arch/i386/kernel/time.c @@ -412,9 +412,9 @@ static int timer_resume(struct sys_devic write_seqlock_irqsave(&xtime_lock, flags); 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; + write_sequnlock_irqrestore(&xtime_lock, flags); if (last_timer->resume) last_timer->resume(); cur_timer = last_timer; - 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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