From: Davidlohr Bueso <dave@stgolabs.net>
To: paulmck@linux.vnet.ibm.com
Cc: linux-kernel@vger.kernel.org, waiman.long@hp.com,
peterz@infradead.org, oleg@redhat.com,
raghavendra.kt@linux.vnet.ibm.com
Subject: Re: BUG: spinlock bad magic on CPU#0, migration/0/9
Date: Wed, 11 Feb 2015 19:15:11 -0800 [thread overview]
Message-ID: <1423710911.2046.50.camel@stgolabs.net> (raw)
In-Reply-To: <20150212003430.GA28656@linux.vnet.ibm.com>
On Wed, 2015-02-11 at 16:34 -0800, Paul E. McKenney wrote:
> Hello!
>
> Did an earlier-than-usual port of v3.21 patches to post-v3.19, and
> hit the following on x86_64. This happened after about 15 minutes of
> rcutorture. In contrast, I have been doing successful 15-hour runs
> on v3.19. I will check reproducibility and try to narrow it down.
> Might this be a duplicate of the bug that Raghavendra posted a fix for?
>
> Anyway, this was on 3e8c04eb1174 (Merge branch 'for-3.20' of
> git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata).
>
> [ 837.287011] BUG: spinlock bad magic on CPU#0, migration/0/9
> [ 837.287013] lock: 0xffff88001ea0fe80, .magic: ffffffff, .owner: gî<81>ÿÿÿÿ/0, .owner_cpu: -42
> [ 837.287013] CPU: 0 PID: 9 Comm: migration/0 Not tainted 3.19.0+ #1
> [ 837.287013] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> [ 837.287013] ffff88001ea0fe80 ffff88001ea0bc78 ffffffff818f6f4b ffffffff810a5a51
> [ 837.287013] ffffffff81e500e0 ffff88001ea0bc98 ffffffff818f3755 ffff88001ea0fe80
> [ 837.287013] ffffffff81ca4396 ffff88001ea0bcb8 ffffffff818f377b ffff88001ea0fe80
> [ 837.287013] Call Trace:
> [ 837.287013] [<ffffffff818f6f4b>] dump_stack+0x45/0x57
> [ 837.287013] [<ffffffff810a5a51>] ? console_unlock+0x1f1/0x4c0
> [ 837.287013] [<ffffffff818f3755>] spin_dump+0x8b/0x90
> [ 837.287013] [<ffffffff818f377b>] spin_bug+0x21/0x26
> [ 837.287013] [<ffffffff8109923c>] do_raw_spin_unlock+0x5c/0xa0
> [ 837.287013] [<ffffffff81902587>] _raw_spin_unlock_irqrestore+0x27/0x50
> [ 837.287013] [<ffffffff8108f0a1>] complete+0x41/0x50
We did have some recent changes in completions:
7c34e318 (sched/completion: Add lock-free checking of the blocking case)
de30ec47 (sched/completion: Remove unnecessary ->wait.lock serialization when reading completion state)
The second one being more related (although both appear to make sense).
Perhaps some subtle implication in the completion_done side that
disappeared with the spinlock?
Thanks,
Davidlohr
next prev parent reply other threads:[~2015-02-12 3:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-12 0:34 BUG: spinlock bad magic on CPU#0, migration/0/9 Paul E. McKenney
2015-02-12 3:15 ` Davidlohr Bueso [this message]
2015-02-12 3:43 ` Paul E. McKenney
2015-02-12 17:28 ` Oleg Nesterov
2015-02-12 17:41 ` Oleg Nesterov
2015-02-12 17:58 ` Davidlohr Bueso
2015-02-12 19:10 ` Nicholas Mc Guire
2015-02-12 19:37 ` Oleg Nesterov
2015-02-12 21:27 ` Oleg Nesterov
2015-02-13 18:17 ` Nicholas Mc Guire
2015-02-13 18:53 ` Oleg Nesterov
2015-02-14 8:35 ` Nicholas Mc Guire
2015-02-14 14:00 ` Oleg Nesterov
2015-02-12 19:59 ` Davidlohr Bueso
2015-02-12 19:32 ` Nicholas Mc Guire
2015-02-12 19:39 ` Oleg Nesterov
2015-02-12 19:59 ` [PATCH] sched/completion: completion_done() should serialize with complete() Oleg Nesterov
2015-02-13 21:09 ` Paul E. McKenney
2015-02-13 21:56 ` Davidlohr Bueso
2015-02-13 22:02 ` Davidlohr Bueso
2015-02-16 8:21 ` Peter Zijlstra
2015-02-16 16:51 ` Oleg Nesterov
2015-02-18 17:06 ` [tip:sched/core] sched/completion: Serialize completion_done() " tip-bot for Oleg Nesterov
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