[PATCH] timekeeping: Add missing update call in timekeeping_resume()

[PATCH] timekeeping: Add missing update call in timekeeping_resume()

[John Stultz]

From: Thomas Gleixner <tglx@linutronix.de>

Linus, 
	Since Thomas is on vacation I wanted to send you his fix to resolve
the suspend regression from the leapsecond fixes.

thanks
-john

The leap second rework unearthed another issue of inconsistent data.

On timekeeping_resume() the timekeeper data is updated, but nothing
calls timekeeping_update(), so now the update code in the timer
interrupt sees stale values.

This has been the case before those changes, but then the timer
interrupt was using stale data as well so this went unnoticed for
quite some time.

Add the missing update call, so all the data is consistent everywhere.

Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Reported-by-and-tested-by: "Rafael J. Wysocki" <rjw@sisk.pl>
CC: LKML <linux-kernel@vger.kernel.org>
Cc: Linux PM list <linux-pm@vger.kernel.org>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
---
 kernel/time/timekeeping.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 269b1fe..3447cfa 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -717,6 +717,7 @@ static void timekeeping_resume(void)
 	timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
 	timekeeper.ntp_error = 0;
 	timekeeping_suspended = 0;
+	timekeeping_update(false);
 	write_sequnlock_irqrestore(&timekeeper.lock, flags);
 
 	touch_softlockup_watchdog();
-- 
1.7.9.5

Re: [PATCH] timekeeping: Add missing update call in timekeeping_resume()

[Konstantin Khlebnikov]

I run into the same regression in s2ram between v3.5-rc6 and v3.5-rc7.
This patch helps. Thanks.

Tested-by: Konstantin Khlebnikov <khlebnikov@openvz.org>

John Stultz wrote:
> From: Thomas Gleixner<tglx@linutronix.de>
>
> Linus,
> 	Since Thomas is on vacation I wanted to send you his fix to resolve
> the suspend regression from the leapsecond fixes.
>
> thanks
> -john
>
> The leap second rework unearthed another issue of inconsistent data.
>
> On timekeeping_resume() the timekeeper data is updated, but nothing
> calls timekeeping_update(), so now the update code in the timer
> interrupt sees stale values.
>
> This has been the case before those changes, but then the timer
> interrupt was using stale data as well so this went unnoticed for
> quite some time.
>
> Add the missing update call, so all the data is consistent everywhere.
>
> Reported-by: Andreas Schwab<schwab@linux-m68k.org>
> Reported-by-and-tested-by: "Rafael J. Wysocki"<rjw@sisk.pl>
> CC: LKML<linux-kernel@vger.kernel.org>
> Cc: Linux PM list<linux-pm@vger.kernel.org>
> Cc: John Stultz<johnstul@us.ibm.com>
> Cc: Ingo Molnar<mingo@kernel.org>
> Cc: Peter Zijlstra<a.p.zijlstra@chello.nl>,
> Cc: Prarit Bhargava<prarit@redhat.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Thomas Gleixner<tglx@linutronix.de>
> Signed-off-by: John Stultz<johnstul@us.ibm.com>
> ---
>   kernel/time/timekeeping.c |    1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index 269b1fe..3447cfa 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -717,6 +717,7 @@ static void timekeeping_resume(void)
>   	timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
>   	timekeeper.ntp_error = 0;
>   	timekeeping_suspended = 0;
> +	timekeeping_update(false);
>   	write_sequnlock_irqrestore(&timekeeper.lock, flags);
>
>   	touch_softlockup_watchdog();