Re: [tip:timers/urgent] hrtimer: Fix /proc/timer_list regression

From: Thomas Gleixner
Date: Thu Nov 19 2009 - 05:08:05 EST


On Thu, 19 Nov 2009, Ingo Molnar wrote:
> i've bisected back to it:
>
> | 887a29f59b93cf54e21814869a4ab6e80b6fa623 is the first bad commit
> | commit 887a29f59b93cf54e21814869a4ab6e80b6fa623
> | Author: Feng Tang <feng.tang@xxxxxxxxx>
> | Date: Thu Sep 3 16:32:53 2009 +0800
> |
> | hrtimer: Fix /proc/timer_list regression
>
> Config attached.
>
> I've removed it from timers/urgent for now.

Come on, this is a patently wrong conclusion.

We call timer_stats_update_stats() which returns on top of the
function due to:

if (likely(!timer_stats_active))
return;

timer_stats_active is 0 during boot and you can only activate it by
writing to /proc/timer_stats which you certainly did not at this
point.

Can you please explain how a call to a function which returns right
away can cause that problem ?

That patch unearthed some other bug and your revert is just papering
over that fact.

Thanks,

tglx
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