From: Valentin Schneider <valentin.schneider@arm.com>
To: John Stultz <john.stultz@linaro.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Quentin Perret <qperret@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Juri Lelli <juri.lelli@redhat.com>,
Patrick Bellasi <Patrick.Bellasi@arm.com>,
Ingo Molnar <mingo@kernel.org>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: Null pointer crash at find_idlest_group on db845c w/ linus/master
Date: Tue, 3 Dec 2019 23:49:11 +0000 [thread overview]
Message-ID: <14a8e456-1f89-0dff-ae89-61e8b6d5593b@arm.com> (raw)
In-Reply-To: <c61cf647-ecb6-b9fa-51f2-8efa36134757@arm.com>
On 03/12/2019 23:20, Valentin Schneider wrote:
> Looking at the code, I think I got it. In find_idlest_group() we do
> initialize 'idlest_sgs' (just like busiest_stat in LB) but 'idlest' is just
> NULL. The latter is dereferenced in update_pick_idlest() just for the misfit
> case, which goes boom. And I reviewed the damn thing... Bleh.
>
> Fixup looks easy enough, lemme write one up.
>
Wait no, that can't be right. We can only get in there if both 'group' and
'idlest' have the same group_type, which can't be true on the first pass.
So if we go through the misfit stuff, idlest *has* to be set to something.
Bah.
next prev parent reply other threads:[~2019-12-03 23:49 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 19:15 John Stultz
2019-12-03 23:20 ` Valentin Schneider
2019-12-03 23:49 ` Valentin Schneider [this message]
2019-12-04 0:13 ` Valentin Schneider
2019-12-04 3:46 ` John Stultz
2019-12-04 10:05 ` Valentin Schneider
2019-12-04 8:06 ` Vincent Guittot
2019-12-04 8:22 ` Vincent Guittot
2019-12-04 9:59 ` Valentin Schneider
2019-12-04 9:42 ` Qais Yousef
2019-12-04 10:09 ` Valentin Schneider
2019-12-04 10:09 ` Vincent Guittot
2019-12-04 10:41 ` Valentin Schneider
2019-12-04 12:08 ` Vincent Guittot
2019-12-04 13:32 ` Qais Yousef
2019-12-04 13:48 ` Vincent Guittot
2019-12-04 13:55 ` Qais Yousef
2019-12-04 14:06 ` Valentin Schneider
2019-12-04 18:16 ` John Stultz
2019-12-04 18:19 ` Vincent Guittot
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