[3.9-rc5 regression, BISECTED] INFO: task umount:29671 blocked formore than 120 seconds

From: Jan Kara
Date: Wed Apr 10 2013 - 08:06:49 EST


Axboe <axboe@xxxxxxxxx>, Phillip Susi <psusi@xxxxxxxxxx>
Bcc:
Subject: Re: [3.9-rc5 regression, BISECTED] INFO: task umount:29671 blocked
for more than 120 seconds
Reply-To:
In-Reply-To: <12072206.85601365230982200.JavaMail.weblogic@epml02>

Hello,

On Sat 06-04-13 06:49:42, Jongman Heo wrote:
> Once I reported this issue (on 1st Apr), and have just done git bisect.
>
> I hit kernel hang with 3.9-rc5, during unmount (the device was mounted via loop device, in case it matters).
This is known problem and I think already fixed. BTW, it's good to CC
author of the patch and the relevant maintainer when you bisected the
problem to a particular patch.

Honza
>
> Steps to reproduce :
> # mount <ISO-9660_iso_image> /mnt -o loop
> # umount /mnt
>
> It's bisected to commit 8761a3dc ("loop: cleanup partitions when detaching loop device").
> Reverting the commit fixes my issue.
>
> 8761a3dc1f07b163414e2215a2cadbb4cfe2a107 is the first bad commit
> commit 8761a3dc1f07b163414e2215a2cadbb4cfe2a107
> Author: Phillip Susi <psusi@xxxxxxxxxx>
> Date: Fri Mar 22 12:21:53 2013 -0600
> loop: cleanup partitions when detaching loop device
>
> Any partitions added by user space to the loop device were being
> left in place after detaching the loop device. This was because
> the detach path issued a BLKRRPART to clean up partitions if
> LO_FLAGS_PARTSCAN was set, meaning that the partitions were auto
> scanned on attach. Replace this BLKRRPART with code that
> unconditionally cleans up partitions on detach instead.
>
> Signed-off-by: Phillip Susi <psusi@xxxxxxxxxx>
>
> Modified by Jens to export delete_partition().
>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> :040000 040000 cb9c85a6b877831e7bb964903de3a01366759ff1 20541f4b522f91861ed02c43e559d0a53252827a M block
> :040000 040000 928d75dba61e6e83fd42fabf5465de56aef9c5b1 f9f4cc9b35c001297740d1d7769e81f8abd3e17d M drivers
>
> # git bisect log
> git bisect start
> # bad: [53f63189b1110559dce8c1ee29e8abc3e31f7630] Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
> git bisect bad 53f63189b1110559dce8c1ee29e8abc3e31f7630
> # good: [19f949f52599ba7c3f67a5897ac6be14bfcb1200] Linux 3.8
> git bisect good 19f949f52599ba7c3f67a5897ac6be14bfcb1200
> # good: [9afa3195b96da7d2320ec44d19fbfbded7a15571] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
> git bisect good 9afa3195b96da7d2320ec44d19fbfbded7a15571
> # good: [9626357371b519f2b955fef399647181034a77fe] Merge tag 'xtensa-next-20130225' of git://github.com/czankel/xtensa-linux
> git bisect good 9626357371b519f2b955fef399647181034a77fe
> # good: [56a79b7b021bf1b08334e63c2c14b280e2dbf47a] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
> git bisect good 56a79b7b021bf1b08334e63c2c14b280e2dbf47a
> # good: [ea4a0ce11160200410abbabd44ec9e75e93a95be] Merge git://git.kernel.org/pub/scm/virt/kvm/kvm
> git bisect good ea4a0ce11160200410abbabd44ec9e75e93a95be
> # good: [630a216da662ba4197e330118fc55d772a2d7ec9] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless into for-davem
> git bisect good 630a216da662ba4197e330118fc55d772a2d7ec9
> # bad: [f8e9248dbb2bddfaed86a14254b7ca2409ef68ff] Merge branch 'for-3.9' of git://linux-nfs.org/~bfields/linux
> git bisect bad f8e9248dbb2bddfaed86a14254b7ca2409ef68ff
> # good: [3615db41c4b82896de450b6b4e3dab2420dcae51] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
> git bisect good 3615db41c4b82896de450b6b4e3dab2420dcae51
> # bad: [a7b436d356d0bdc6156e286f9c251beed1961d2d] Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
> git bisect bad a7b436d356d0bdc6156e286f9c251beed1961d2d
> # bad: [d8d595dfce7925627de78b9eecc8598a6ffda610] block: removes dynamic allocation on stack
> git bisect bad d8d595dfce7925627de78b9eecc8598a6ffda610
> # good: [b1173e316bf2ff3c11f46247417f0f5789a4ea0c] xen-blkfront: remove frame list from blk_shadow
> git bisect good b1173e316bf2ff3c11f46247417f0f5789a4ea0c
> # good: [351a2c6e7d265f97799ec7f6b1dde7fc7cb4b92d] rsxx: fix missing unlock on error return in rsxx_eeh_remap_dmas()
> git bisect good 351a2c6e7d265f97799ec7f6b1dde7fc7cb4b92d
> # good: [183cfb5720dfc393641b87710ce78561af3db6cd] loop: fix error return code in loop_add()
> git bisect good 183cfb5720dfc393641b87710ce78561af3db6cd
> # bad: [d2b805d89510737ea80c1469f854a16480d19778] cciss: fix invalid use of sizeof in cciss_find_cfgtables()
> git bisect bad d2b805d89510737ea80c1469f854a16480d19778
> # bad: [8761a3dc1f07b163414e2215a2cadbb4cfe2a107] loop: cleanup partitions when detaching loop device
> git bisect bad 8761a3dc1f07b163414e2215a2cadbb4cfe2a107
>
>
> [ 3600.583547] INFO: task umount:29671 blocked for more than 120 seconds.
> [ 3600.583552] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [ 3600.583555] umount D 0000000000000001 0 29671 29632 0x00000000
> [ 3600.583561] ffff88011ecb5c98 0000000000000086 ffff880130ccade0 0000000000013e40
> [ 3600.583566] ffff88011ecb5fd8 ffff88011ecb4010 0000000000013e40 0000000000013e40
> [ 3600.583571] ffff88011ecb5fd8 0000000000013e40 ffff880132518000 ffff880130ccade0
> [ 3600.583575] Call Trace:
> [ 3600.583583] [<ffffffff816fb669>] schedule+0x29/0x70
> [ 3600.583589] [<ffffffff816fb98e>] schedule_preempt_disabled+0xe/0x10
> [ 3600.583593] [<ffffffff816fa0af>] __mutex_lock_slowpath+0xdf/0x160
> [ 3600.583598] [<ffffffff811e433e>] ? release_sysfs_dirent+0x7e/0x100
> [ 3600.583603] [<ffffffff816f9fab>] mutex_lock+0x2b/0x50
> [ 3600.583607] [<ffffffff8149a8aa>] loop_clr_fd+0x24a/0x2e0
> [ 3600.583612] [<ffffffff816fce3e>] ? _raw_spin_lock+0xe/0x20
> [ 3600.583617] [<ffffffff8149a9b8>] lo_release+0x78/0x90
> [ 3600.583622] [<ffffffff811a94e4>] __blkdev_put+0x194/0x1d0
> [ 3600.583628] [<ffffffff811a957d>] blkdev_put+0x5d/0x160
> [ 3600.583633] [<ffffffff811719bd>] kill_block_super+0x4d/0x80
> [ 3600.583638] [<ffffffff81171f35>] deactivate_locked_super+0x45/0x70
> [ 3600.583643] [<ffffffff81172dda>] deactivate_super+0x4a/0x70
> [ 3600.583648] [<ffffffff8118e538>] mntput_no_expire+0xf8/0x150
> [ 3600.583653] [<ffffffff8118eded>] sys_umount+0xcd/0x3e0
> [ 3600.583659] [<ffffffff817058d9>] system_call_fastpath+0x16/0x1b
> [ 3600.583663] INFO: task blkid:29673 blocked for more than 120 seconds.
> [ 3600.583665] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [ 3600.583667] blkid D ffffffff81807f20 0 29673 1 0x00000000
> [ 3600.583672] ffff88011338fa88 0000000000000082 ffff880130ccc4d0 0000000000013e40
> [ 3600.583677] ffff88011338ffd8 ffff88011338e010 0000000000013e40 0000000000013e40
> [ 3600.583681] ffff88011338ffd8 0000000000013e40 ffff880132b416f0 ffff880130ccc4d0
> [ 3600.583686] Call Trace:
> [ 3600.583691] [<ffffffff816fb669>] schedule+0x29/0x70
> [ 3600.583695] [<ffffffff816fb98e>] schedule_preempt_disabled+0xe/0x10
> [ 3600.583700] [<ffffffff816fa0af>] __mutex_lock_slowpath+0xdf/0x160
> [ 3600.583704] [<ffffffff816f9fab>] mutex_lock+0x2b/0x50
> [ 3600.583709] [<ffffffff811a9723>] __blkdev_get+0x73/0x480
> [ 3600.583714] [<ffffffff811a9e90>] ? blkdev_get+0x360/0x360
> [ 3600.583719] [<ffffffff811a9b81>] blkdev_get+0x51/0x360
> [ 3600.583724] [<ffffffff816fce3e>] ? _raw_spin_lock+0xe/0x20
> [ 3600.583729] [<ffffffff811a9e90>] ? blkdev_get+0x360/0x360
> [ 3600.583734] [<ffffffff811a9ef2>] blkdev_open+0x62/0x80
> [ 3600.583739] [<ffffffff8116d82e>] do_dentry_open+0x23e/0x2c0
> [ 3600.583743] [<ffffffff8116d9c5>] finish_open+0x35/0x50
> [ 3600.583748] [<ffffffff8117c7b6>] do_last+0x696/0xe50
> [ 3600.583752] [<ffffffff81166984>] ? kmem_cache_alloc_trace+0xc4/0x120
> [ 3600.583757] [<ffffffff8117f7c8>] path_openat+0xb8/0x490
> [ 3600.583762] [<ffffffff8117fcd9>] do_filp_open+0x49/0xa0
> [ 3600.583767] [<ffffffff816fce3e>] ? _raw_spin_lock+0xe/0x20
> [ 3600.583772] [<ffffffff8118c4e5>] ? __alloc_fd+0xb5/0x160
> [ 3600.583777] [<ffffffff8116d498>] do_sys_open+0x108/0x1f0
> [ 3600.583781] [<ffffffff8116d5c1>] sys_open+0x21/0x30
> [ 3600.583786] [<ffffffff817058d9>] system_call_fastpath+0x16/0x1b
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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