Re: [RESEND][PATCH] Fix oops on !GENERIC_TIME systems whenaccessing current_clocksource

From: john stultz
Date: Mon Mar 08 2010 - 16:22:21 EST


On Mon, 2010-03-01 at 12:34 -0800, john stultz wrote:
> No one has replied to this, so I wanted to send it out again.

Just another ping here. I know the patch has made it to -tip, but its
something that should be needed for 2.6.34, 2.6.33-stable.

thanks
-john


> Aaro Koskinen reported an issue in bug #15366, where on non-GENERIC_TIME
> systems,
> accessing /sys/devices/system/clocksource/clocksource0/current_clocksource would oops the system.
>
> It seems the timekeeper/clocksource rework missed initializing the
> curr_clocksource value in the !GENERIC_TIME.
>
> The following patch makes sure it gets initialized, and avoids the
> issue.
>
> Thanks to Aaro for reporting and diagnosing the issue as well as testing
> the fix!
>
> Bug Details: http://bugzilla.kernel.org/show_bug.cgi?id=15366
>
> Too late for 2.6.33, but this likely should go into 2.6.33-stable and
> 2.6.32-stable.
>
> thanks
> -john
>
>
> Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>
>
> diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> index e85c234..c436ee5 100644
> --- a/kernel/time/clocksource.c
> +++ b/kernel/time/clocksource.c
> @@ -568,6 +568,10 @@ static inline void clocksource_select(void) { }
> */
> static int __init clocksource_done_booting(void)
> {
> + mutex_lock(&clocksource_mutex);
> + curr_clocksource = clocksource_default_clock();
> + mutex_unlock(&clocksource_mutex);
> +
> finished_booting = 1;
>
> /*
>
>


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