Re: CIFS-related deadlock in 3.10-rc7

From: Pavel Shilovsky
Date: Thu Jul 11 2013 - 08:53:25 EST


2013/7/7 Alexander E. Patrakov <patrakov@xxxxxxxxx>:
> While playing a file from a CIFS-mounted samba share (over wireless,
> if that matters), I got this deadlock:
>
> [ 2164.132440] =============================================
> [ 2164.132443] [ INFO: possible recursive locking detected ]
> [ 2164.132446] 3.10.0-rc7-rafael+ #26 Tainted: G C
> [ 2164.132448] ---------------------------------------------
> [ 2164.132452] vlc/2370 is trying to acquire lock:
> [ 2164.132454] (&cifsi->lock_sem){++++.+}, at: [<ffffffffa0913110>]
> cifs_reopen_file+0x270/0x5b0 [cifs]
> [ 2164.132472]
> but task is already holding lock:
> [ 2164.132475] (&cifsi->lock_sem){++++.+}, at: [<ffffffffa0918ca8>]
> cifs_strict_readv+0x88/0x160 [cifs]
> [ 2164.132488]
> other info that might help us debug this:
> [ 2164.132491] Possible unsafe locking scenario:
>
> [ 2164.132494] CPU0
> [ 2164.132496] ----
> [ 2164.132498] lock(&cifsi->lock_sem);
> [ 2164.132502] lock(&cifsi->lock_sem);
> [ 2164.132505]
> *** DEADLOCK ***
>
> [ 2164.132508] May be due to missing lock nesting notation
>
> [ 2164.132511] 1 lock held by vlc/2370:
> [ 2164.132513] #0: (&cifsi->lock_sem){++++.+}, at:
> [<ffffffffa0918ca8>] cifs_strict_readv+0x88/0x160 [cifs]
> [ 2164.132526]
> stack backtrace:
> [ 2164.132531] CPU: 3 PID: 2370 Comm: vlc Tainted: G C
> 3.10.0-rc7-rafael+ #26
> [ 2164.132534] Hardware name: Sony Corporation VPCZ23A4R/VAIO, BIOS
> R1013H5 05/21/2012
> [ 2164.132537] ffff880235033f80 ffff8802281fb958 ffffffff8165b7ae
> ffff8802281fba48
> [ 2164.132544] ffffffff810a0042 ffff8802281fb978 ffffffff826360d0
> ffff8802281fb9c8
> [ 2164.132550] 0000000000000000 0000000000000000 00000000000389b0
> ffff880200000542
> [ 2164.132556] Call Trace:
> [ 2164.132564] [<ffffffff8165b7ae>] dump_stack+0x19/0x1b
> [ 2164.132569] [<ffffffff810a0042>] __lock_acquire+0x1522/0x1ee0
> [ 2164.132579] [<ffffffffa091aa41>] ? cifs_get_inode_info+0x181/0x690 [cifs]
> [ 2164.132587] [<ffffffffa0913110>] ? cifs_reopen_file+0x270/0x5b0 [cifs]
> [ 2164.132591] [<ffffffff810a1027>] lock_acquire+0x87/0x150
> [ 2164.132598] [<ffffffffa0913110>] ? cifs_reopen_file+0x270/0x5b0 [cifs]
> [ 2164.132604] [<ffffffff8165ed3f>] down_write+0x3f/0x70
> [ 2164.132612] [<ffffffffa0913110>] ? cifs_reopen_file+0x270/0x5b0 [cifs]
> [ 2164.132622] [<ffffffffa0927a76>] ? cifs_set_fid+0x26/0x40 [cifs]
> [ 2164.132632] [<ffffffffa0913110>] cifs_reopen_file+0x270/0x5b0 [cifs]
> [ 2164.132642] [<ffffffffa0913d0b>] cifs_readpage_worker+0x1ab/0x4e0 [cifs]
> [ 2164.132652] [<ffffffffa091427e>] cifs_readpage+0x5e/0x160 [cifs]
> [ 2164.132660] [<ffffffff81109b87>] generic_file_aio_read+0x217/0x760
> [ 2164.132670] [<ffffffffa0918d51>] cifs_strict_readv+0x131/0x160 [cifs]
> [ 2164.132675] [<ffffffff8116fff5>] do_sync_read+0x75/0xb0
> [ 2164.132681] [<ffffffff81170ef7>] vfs_read+0xa7/0x180
> [ 2164.132686] [<ffffffff81171170>] SyS_read+0x50/0xa0
> [ 2164.132691] [<ffffffff81668e16>] system_call_fastpath+0x1a/0x1f
>
> --
> Alexander E. Patrakov
> --
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Thank you for pointing it out. I created a patch that should fix the
problem - will sent separately.

--
Best regards,
Pavel Shilovsky.
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