Re: [PATCH] sched_fair.c:find_busiest_group(), kernel 2.6.35.7

From: Peter Zijlstra
Date: Wed Oct 20 2010 - 07:18:05 EST


On Wed, 2010-10-20 at 00:20 -0700, Andrew Dickinson wrote:
> This is a patch to fix the corner case where we're crashing with
> divide_error in find_busiest_group (see
> https://bugzilla.kernel.org/show_bug.cgi?id=16991).
> I don't fully understand what the case is that causes sds.total_pwr to
> be zero in find_busiest_group, but this patch guards against the
> divide-by-zero bug.
>
> I also added safe-guarding around other routines in the scheduler code
> where we're dividing by power; that's more of a just-in-case and I'm
> definitely open for debate on that.

No.. papering over crap like this is not done. In that BZ there's a
number of suggestions of how/where to track down the actual root cause,
but apparently nobody is interested in doing that.

(I can't reproduce so I can't actually do anything about it).
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