From: Andi Kleen <ak@linux.intel.com>
To: syzbot <syzbot+283c3c447181741aea28@syzkaller.appspotmail.com>
Cc: akpm@linux-foundation.org, aryabinin@virtuozzo.com, jack@suse.cz,
jlayton@redhat.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, mgorman@techsingularity.net,
mingo@kernel.org, rgoldwyn@suse.com,
syzkaller-bugs@googlegroups.com, linux-fsdevel@vger.kernel.org
Subject: Re: INFO: task hung in sync_blockdev
Date: Wed, 7 Feb 2018 07:52:29 -0800 [thread overview]
Message-ID: <20180207155229.GC10945@tassilo.jf.intel.com> (raw)
In-Reply-To: <001a11447070ac6fcb0564a08cb1@google.com>
> #0: (&bdev->bd_mutex){+.+.}, at: [<0000000040269370>]
> __blkdev_put+0xbc/0x7f0 fs/block_dev.c:1757
> 1 lock held by blkid/19199:
> #0: (&bdev->bd_mutex){+.+.}, at: [<00000000b4dcaa18>]
> __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
> #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000033edf9f2>]
> n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
> 1 lock held by syz-executor5/19330:
> #0: (&bdev->bd_mutex){+.+.}, at: [<00000000b4dcaa18>]
> __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
> 1 lock held by syz-executor5/19331:
> #0: (&bdev->bd_mutex){+.+.}, at: [<00000000b4dcaa18>]
> __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
It seems multiple processes deadlocked on the bd_mutex.
Unfortunately there's no backtrace for the lock acquisitions,
so it's hard to see the exact sequence.
It seems lockdep is already active, so it's likely not
just an ordering violation, but something else.
-Andi
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next parent reply other threads:[~2018-02-07 15:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <001a11447070ac6fcb0564a08cb1@google.com>
2018-02-07 15:52 ` Andi Kleen [this message]
2018-02-08 9:28 ` INFO: task hung in sync_blockdev Jan Kara
2018-02-08 13:28 ` Dmitry Vyukov
2018-02-08 14:08 ` Jan Kara
2018-02-08 14:18 ` Dmitry Vyukov
2018-02-08 16:18 ` Jan Kara
2018-02-08 16:23 ` Andrey Ryabinin
2018-02-08 17:17 ` Dmitry Vyukov
2018-02-09 15:31 ` Andrey Ryabinin
2018-02-08 14:49 ` Andi Kleen
2018-02-08 16:20 ` Jan Kara
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