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: Thu, 11 Apr 2013 21:48:16 +0200 (CEST) [thread overview]
Message-ID: <alpine.LFD.2.02.1304112146230.21884@ionos> (raw)
In-Reply-To: <5166FBFB.2030703@sr71.net>
On Thu, 11 Apr 2013, Dave Hansen wrote:
> On 04/11/2013 03:19 AM, Thomas Gleixner wrote:
> > --- linux-2.6.orig/kernel/smpboot.c
> > +++ linux-2.6/kernel/smpboot.c
> > @@ -185,8 +185,18 @@ __smpboot_create_thread(struct smp_hotpl
> > }
> > get_task_struct(tsk);
> > *per_cpu_ptr(ht->store, cpu) = tsk;
> > - if (ht->create)
> > - ht->create(cpu);
> > + if (ht->create) {
> > + /*
> > + * Make sure that the task has actually scheduled out
> > + * into park position, before calling the create
> > + * callback. At least the migration thread callback
> > + * requires that the task is off the runqueue.
> > + */
> > + if (!wait_task_inactive(tsk, TASK_PARKED))
> > + WARN_ON(1);
> > + else
> > + ht->create(cpu);
> > + }
> > return 0;
> > }
>
> This one appears to be doing the trick. I'll run the cpus in an
> online/offline loop for a bit and make sure it's stable. It's passed
> several round so far, which is way more than it's done up to this point,
> though.
I think the most critical part is bootup when the threads are
created. The online/offline one is an issue as well, which is covered
by the patches, but way harder to trigger.
Thanks,
tglx
next prev parent reply other threads:[~2013-04-11 19:48 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
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 [this message]
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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