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Date: Wed, 30 Jul 2003 16:54:18 -0700
From: Andrew Morton <akpm@osdl.org>
To: Andrea Arcangeli <andrea@suse.de>
Cc: linas@austin.ibm.com, mingo@elte.hu, linux-kernel@vger.kernel.org,
       olh@suse.de, olof@austin.bim.com
Subject: Re: PATCH: Race in 2.6.0-test2 timer code
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Andrea Arcangeli <andrea@suse.de> wrote:
>
> 2.6 will kernel crash like we did in 2.4 only if it calls
> add_timer_on from timer context (of course with a cpuid != than the
> smp_processor_id()), that would be fixed by the timer->lock everywhere
> that we've in 2.4 right now.  (but there's no add_timer_on in 2.4
> anyways)

add_timer_on() was added specifically for slab bringup.  If we need extra
locking to cope with it then the best solution would probably be to rename
it to add_timer_on_dont_use_this_for_anything_else().

But if we are going to rely on timer handlers only ever running on the
adding CPU for locking purposes then can we please have a big comment
somewhere describing what's going on?  It's very subtle...