From: Peter Zijlstra <peterz@infradead.org>
To: "Michel Dänzer" <michel@daenzer.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
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: Thu, 24 Jul 2014 11:55:17 +0200 [thread overview]
Message-ID: <20140724095517.GS12054@laptop.lan> (raw)
In-Reply-To: <20140724075157.GJ3935@laptop>
On Thu, Jul 24, 2014 at 09:51:57AM +0200, Peter Zijlstra wrote:
> > I hope the assembly output I sent earlier helps, I'm afraid bisecting
> > this could be painful.
>
> Yeah, lemme go have a look...
So I'm not seeing it, the cpus value is kept at -136(%rbp), so
-128(%rbp) comes after and that's struct lb_env env. And -140(%rbp)
comes before and that ends up being @idle.
The compiler likes to spill for sure, but aside from stupid I don't
see it doing wrong in the relatively short code from function start to
the rep movsl.
It does a rep stosl on -128(%rbp) and then fills it out, but none of
that looks to stomp on our -136(%rbp) value. And the -140(%rbp) thing is
only written to once, and while that is done after the 136 thing its a
single movl and that's not going to clobber anything.
And the fault happens before we pass @env around, so there no chance
someone writes before it either.
So I'm still entirely clueless..
prev parent reply other threads:[~2014-07-24 9:55 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
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 [this message]
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