From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Michel Dänzer" <michel@daenzer.net>,
"Ingo Molnar" <mingo@redhat.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: Random panic in load_balance() with 3.16-rc
Date: Wed, 23 Jul 2014 08:49:48 +0200 [thread overview]
Message-ID: <20140723064948.GK3935@laptop> (raw)
In-Reply-To: <CA+55aFwyURgG717kmuAXzKcHddN_63GirtwHZB4ePKH+8qVtJw@mail.gmail.com>
On Tue, Jul 22, 2014 at 09:21:40PM -0700, Linus Torvalds wrote:
> On Tue, Jul 22, 2014 at 8:53 PM, Michel Dänzer <michel@daenzer.net> wrote:
> >
> > Just happened again with the same change on top of 3.16-rc6.
>
> The (maybe) related bugzilla entry is just odd. Bruno Wolff reports
> that the BUG_ON() in his added patch triggers:
>
> + cpumask_clear(sched_group_cpus(sg));
> + sg->sgc->capacity = 0;
> + BUG_ON(!cpumask_empty(sched_group_cpus(sg)));
>
> where it *just* did a cpumask_clear(), and now the BUG_ON() triggers
> that it's no longer empty?
>
> That would imply an allocation error, but all the sched groups seem to
> be properly allocated with the proper addition of cpumask_size().
>
> And his config file even has NR_CPUS being 32, so it should be a
> single word of bitmap, which triggers all the simple code.
>
> Completely insane, in other words.
So we've had this other thread where the same happened:
lkml.kernel.org/r/20140716145546.GA6922@wolff.to
(pointed Michel to that earlier)
And that seems to be sorted now (just found positive feedback in my
Inbox this morning), it was a question of the arch code supplying
completely 'broken' topology information, and the scheduler trusting it
too much.
The real fix in that thread is:
lkml.kernel.org/r/20140722133514.GM12054@laptop.lan
And I'll also add this to make the scheduler less trusting:
lkml.kernel.org/r/20140722094740.GJ12054@laptop.lan
Michael, that's not going to tell us what's wrong with your machine, as
you've not got the ancient dual P4 Xeon Bruno's got. Seeing how your
cpuinfo says:
model name : AMD A10-7850K Radeon R7, 12 Compute Cores 4C+8G
but we can start the same debugging session I suppose.
Could you run with this patch on top:
lkml.kernel.org/r/20140718101633.GP9918@twins.programming.kicks-ass.net
And provide us with the dmesg after boot?
next prev parent reply other threads:[~2014-07-23 6:49 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <53C77BB8.6030804@daenzer.net>
2014-07-17 7:58 ` Random panic in load_balance() with 3.16-rc Peter Zijlstra
2014-07-18 9:29 ` Michel Dänzer
2014-07-22 6:13 ` Michel Dänzer
2014-07-23 3:53 ` Michel Dänzer
2014-07-23 4:21 ` Linus Torvalds
2014-07-23 6:49 ` Peter Zijlstra [this message]
2014-07-23 8:05 ` Michel Dänzer
2014-07-23 8:28 ` Peter Zijlstra
2014-07-23 9:25 ` Peter Zijlstra
2014-07-23 9:31 ` Michel Dänzer
2014-07-23 9:45 ` Dietmar Eggemann
2014-07-23 11:11 ` Peter Zijlstra
2014-07-23 11:30 ` Peter Zijlstra
2014-07-23 14:24 ` Peter Zijlstra
2014-07-23 14:38 ` Michel Dänzer
2014-07-23 15:51 ` Linus Torvalds
[not found] ` <20140723155526.GW3935@laptop>
2014-07-23 16:54 ` Linus Torvalds
2014-07-23 17:03 ` Peter Zijlstra
2014-07-23 17:12 ` Linus Torvalds
2014-07-23 17:26 ` Linus Torvalds
2014-07-23 18:25 ` Peter Zijlstra
2014-07-23 18:35 ` Linus Torvalds
2014-07-23 18:41 ` Peter Zijlstra
2014-07-23 18:55 ` Linus Torvalds
2014-07-23 19:02 ` Peter Zijlstra
2014-07-23 19:20 ` Linus Torvalds
2014-07-24 1:43 ` Michel Dänzer
2014-07-24 18:47 ` Linus Torvalds
2014-07-24 18:59 ` Peter Zijlstra
2014-07-25 1:25 ` Michel Dänzer
2014-07-25 2:33 ` Linus Torvalds
2014-07-25 2:50 ` Nick Krause
2014-07-25 2:36 ` Nick Krause
2014-07-25 3:55 ` Alexei Starovoitov
2014-07-25 4:00 ` Nick Krause
2014-07-25 14:02 ` Steven Rostedt
2014-07-25 18:29 ` Linus Torvalds
2014-07-25 19:10 ` Steven Rostedt
2014-07-25 20:01 ` Linus Torvalds
2014-07-25 20:13 ` Steven Rostedt
2014-07-25 21:25 ` Jakub Jelinek
2014-07-26 18:28 ` Linus Torvalds
2014-07-26 18:39 ` Linus Torvalds
2014-07-26 19:35 ` Markus Trippelsdorf
2014-07-26 19:55 ` Theodore Ts'o
2014-07-26 20:20 ` Markus Trippelsdorf
2014-07-26 22:08 ` Jakub Jelinek
2014-07-26 19:56 ` Linus Torvalds
2014-07-26 20:03 ` Linus Torvalds
2014-07-26 20:19 ` Markus Trippelsdorf
2014-07-26 20:39 ` Linus Torvalds
2014-07-28 12:26 ` Frank Ch. Eigler
2014-07-28 13:10 ` Theodore Ts'o
2014-07-28 14:11 ` Frank Ch. Eigler
2014-07-28 16:45 ` Linus Torvalds
2014-07-28 17:27 ` Alexei Starovoitov
2014-07-28 18:09 ` Markus Trippelsdorf
2014-07-28 18:28 ` Linus Torvalds
2014-07-28 18:41 ` Markus Trippelsdorf
2014-07-29 8:58 ` Jakub Jelinek
2014-07-28 19:50 ` Theodore Ts'o
2014-07-28 3:47 ` Michel Dänzer
2014-07-28 16:48 ` Linus Torvalds
2014-07-29 2:29 ` Michel Dänzer
2014-08-05 3:19 ` Steven Rostedt
2014-07-26 18:02 ` Steven Chamberlain
2014-07-29 9:20 ` Michel Dänzer
2014-07-25 6:48 ` Jakub Jelinek
2014-07-25 8:15 ` Linus Torvalds
2014-07-25 9:03 ` Michel Dänzer
2014-07-25 9:21 ` Markus Trippelsdorf
2014-07-25 9:42 ` Markus Trippelsdorf
2014-07-23 18:07 ` Linus Torvalds
2014-07-23 18:31 ` Peter Zijlstra
2014-07-23 18:24 ` Peter Zijlstra
2014-07-23 17:04 ` Peter Zijlstra
2014-07-23 17:15 ` Linus Torvalds
2014-07-23 18:25 ` Peter Zijlstra
2014-07-23 18:23 ` Peter Zijlstra
2014-07-23 10:52 ` Peter Zijlstra
2014-07-24 7:18 ` Michel Dänzer
2014-07-24 7:51 ` Peter Zijlstra
2014-07-24 9:55 ` Peter Zijlstra
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