From: Sasha Levin <sashal@kernel.org>
To: Corey Wright <undefined@pobox.com>
Cc: stable@vger.kernel.org
Subject: Re: [PATCH 3.18 0/1] dm: remove duplicate dm_get_live_table() in __dm_destroy()
Date: Sun, 11 Nov 2018 17:20:15 -0500 [thread overview]
Message-ID: <20181111222015.GC2642@sasha-vm> (raw)
In-Reply-To: <20181111020654.b09fd2621617745e39ba694c@pobox.com>
On Sun, Nov 11, 2018 at 02:06:54AM -0600, Corey Wright wrote:
>The recently released stable version 3.18.125 introduced a deadlock
>because dm_get_live_table() is called twice within __dm_destroy().
>
>The backported commit e1db66a5 "dm: fix AB-BA deadlock in
>__dm_destroy()" doesn't *move* the dm_get_live_table() call from
>before the mutex_lock(), as the original commit 2a708cff does, but
>instead *adds* a new dm_get_live_table() call after the mutex_lock().
>The two dm_get_live_table() calls result in a deadlock:
>
>[ 311.291323] INFO: task cryptsetup:209 blocked for more than 120 seconds.
>[ 311.420925] Not tainted 3.18.125+1-amd64 #1
>[ 311.559858] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>[ 311.651116] cryptsetup D 0000000000000000 0 209 203 0x00000000
>[ 311.732304] ffff88007abfd5f0 0000000000000082 0000000000000001 ffff88007a470390
>[ 311.873420] 00000000000136c0 ffff88007a78bfd8 00000000000136c0 ffff88007abfd5f0
>[ 311.934275] 0000000000000001 ffff88007a78bc70 7fffffffffffffff ffff88007a78bc68
>[ 311.940115] Call Trace:
>[ 311.949956] [<ffffffffa01d0b70>] ? dev_suspend+0x260/0x260 [dm_mod]
>[ 312.179891] [<ffffffff81553d8a>] ? schedule_timeout+0x24a/0x2d0
>[ 312.375447] [<ffffffff810a7ba4>] ? __wake_up+0x34/0x50
>[ 312.377825] [<ffffffff810c3374>] ? srcu_readers_seq_idx.isra.8+0x54/0x70
>[ 312.557921] [<ffffffff815519b0>] ? wait_for_completion+0xb0/0x120
>[ 312.561314] [<ffffffff81096340>] ? wake_up_state+0x20/0x20
>[ 312.664457] [<ffffffff810c36e8>] ? __synchronize_srcu+0xd8/0x120
>[ 312.768794] [<ffffffff810c3260>] ? call_srcu+0x70/0x70
>[ 312.790337] [<ffffffffa01ca757>] ? __dm_destroy+0x107/0x2e0 [dm_mod]
>[ 312.909878] [<ffffffffa01d0b70>] ? dev_suspend+0x260/0x260 [dm_mod]
>[ 312.978804] [<ffffffffa01d0c4e>] ? dev_remove+0xde/0x120 [dm_mod]
>[ 313.082322] [<ffffffffa01d12e3>] ? ctl_ioctl+0x203/0x4c0 [dm_mod]
>[ 313.175957] [<ffffffffa01d15b3>] ? dm_ctl_ioctl+0x13/0x20 [dm_mod]
>[ 313.301981] [<ffffffff811d40c0>] ? do_vfs_ioctl+0x2d0/0x4a0
>[ 313.384648] [<ffffffff8108848c>] ? task_work_run+0xbc/0xf0
>[ 313.489669] [<ffffffff811d4311>] ? SyS_ioctl+0x81/0xa0
>[ 313.510846] [<ffffffff815551cd>] ? system_call_fastpath+0x16/0x1b
>
>Removing the original dm_get_live_table() call from before the
>mutex_lock() prevents the deadlock.
>
>Thanks for maintaining 3.18!
>
>PS Greg, Was this a subtle attempt to get someone to speak up and say
> "I am using this!" as you requested in the 3.18.125 release
> announcement? ;)
Hm, interesting. It looks like git did the wrong thing here, sorry for
that :(
--
Thanks,
Sasha
prev parent reply other threads:[~2018-11-12 8:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-11 8:06 [PATCH 3.18 0/1] dm: remove duplicate dm_get_live_table() in __dm_destroy() Corey Wright
2018-11-11 8:22 ` [PATCH 3.18 1/1] " Corey Wright
2018-11-11 20:53 ` [PATCH 3.18 0/1] " Greg KH
2018-11-12 2:03 ` Corey Wright
2018-11-11 22:20 ` Sasha Levin [this message]
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