Atsushi Nemoto <[email protected]> wrote:
>
> >>>>> On Thu, 2 Mar 2006 10:43:12 -0600, "Ram Gupta" <[email protected]> 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 <[email protected]>
>
> 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;
Thanks, that looks like 2.6.16 material.
What happens if the machine slept for more than 49.7 days?
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