From: Thomas Gleixner <tglx@linutronix.de>
To: Dave Hansen <dave@sr71.net>
Cc: Borislav Petkov <bp@alien8.de>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
Dave Jones <davej@redhat.com>,
dhillf@gmail.com, Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] kthread: Prevent unpark race which puts threads on the wrong cpu
Date: Wed, 10 Apr 2013 12:51:15 +0200 (CEST) [thread overview]
Message-ID: <alpine.LFD.2.02.1304101250320.21884@ionos> (raw)
In-Reply-To: <alpine.LFD.2.02.1304101024010.21884@ionos>
On Wed, 10 Apr 2013, Thomas Gleixner wrote:
> On Tue, 9 Apr 2013, Dave Hansen wrote:
>
> > On 04/09/2013 12:30 PM, Thomas Gleixner wrote:
> > > On Tue, 9 Apr 2013, Thomas Gleixner wrote:
> > > Thought more about it and found, that the stupid binding only works
> > > when the task is really descheduled. So there is a small window left,
> > > which could lead to this. Revised patch below.
> > >
> > > Anyway a trace for that issue would be appreciated nevertheless.
> >
> > Here you go:
> >
> > http://sr71.net/~dave/linux/bigbox.1365539189.txt.gz
>
> Hmm. Unfortunately migration/146 is not in the trace.
>
> Can you please apply the patch below? That avoids the oops, but might
> hang an online operation. Though the machine should stay up and you
> should be able to retrieve the trace.
>
> Thanks,
>
> tglx
> ---
> Index: linux-2.6/kernel/smpboot.c
> ===================================================================
> --- linux-2.6.orig/kernel/smpboot.c
> +++ linux-2.6/kernel/smpboot.c
> @@ -131,7 +131,10 @@ static int smpboot_thread_fn(void *data)
> continue;
> }
>
> - BUG_ON(td->cpu != smp_processor_id());
> + if (td->cpu != smp_processor_id()) {
> + tracing_off();
> + schedule();
Bah, that wants a continue. Revised patch below.
> + }
>
> /* Check for state change setup */
> switch (td->status) {
Index: linux-2.6/kernel/smpboot.c
===================================================================
--- linux-2.6.orig/kernel/smpboot.c
+++ linux-2.6/kernel/smpboot.c
@@ -131,7 +131,11 @@ static int smpboot_thread_fn(void *data)
continue;
}
- BUG_ON(td->cpu != smp_processor_id());
+ if (td->cpu != smp_processor_id()) {
+ tracing_off();
+ schedule();
+ continue;
+ }
/* Check for state change setup */
switch (td->status) {
next prev parent reply other threads:[~2013-04-10 10:51 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-05 21:43 kernel BUG at kernel/smpboot.c:134! Dave Hansen
2013-04-06 7:12 ` Srivatsa S. Bhat
2013-04-06 8:31 ` Thomas Gleixner
2013-04-07 9:20 ` Thomas Gleixner
2013-04-07 9:50 ` Borislav Petkov
2013-04-08 9:24 ` Thomas Gleixner
2013-04-08 11:55 ` Borislav Petkov
2013-04-08 12:17 ` Thomas Gleixner
2013-04-09 14:38 ` [PATCH] kthread: Prevent unpark race which puts threads on the wrong cpu Thomas Gleixner
2013-04-09 15:55 ` Dave Hansen
2013-04-09 18:43 ` Thomas Gleixner
2013-04-09 19:30 ` Thomas Gleixner
2013-04-09 20:38 ` Dave Hansen
2013-04-09 20:54 ` Dave Hansen
2013-04-10 8:29 ` Thomas Gleixner
2013-04-10 10:51 ` Thomas Gleixner [this message]
2013-04-10 19:41 ` Dave Hansen
2013-04-11 10:19 ` Thomas Gleixner
2013-04-11 10:48 ` Srivatsa S. Bhat
2013-04-11 11:43 ` Srivatsa S. Bhat
2013-04-11 11:59 ` Srivatsa S. Bhat
2013-04-11 12:51 ` Thomas Gleixner
2013-04-11 12:54 ` Thomas Gleixner
2013-04-11 13:46 ` Thomas Gleixner
2013-04-11 18:07 ` Dave Hansen
2013-04-11 19:48 ` Thomas Gleixner
2013-04-10 14:03 ` [PATCH] CPU hotplug, smpboot: Fix crash in smpboot_thread_fn() Srivatsa S. Bhat
2013-04-11 8:10 ` Thomas Gleixner
2013-04-11 10:19 ` Srivatsa S. Bhat
2013-04-11 19:16 ` [PATCH] kthread: Prevent unpark race which puts threads on the wrong cpu Srivatsa S. Bhat
2013-04-11 20:47 ` Thomas Gleixner
2013-04-11 21:19 ` Srivatsa S. Bhat
2013-04-12 10:59 ` Thomas Gleixner
2013-04-12 11:26 ` Srivatsa S. Bhat
2013-04-15 19:49 ` Dave Hansen
2013-04-12 10:41 ` Peter Zijlstra
2013-04-12 12:32 ` [tip:core/urgent] " tip-bot for Thomas Gleixner
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