[Virtual-pkg-base-maintainers] Bug#692571: INFO: task blocked for more than 120 seconds when access to Logical Volume

[Thomas Boutelier]

Package: base
Severity: normal

I have a script who makes backup of virtual machine each weeks. I create snapshot of volume group, then I 
backup it with dd. Sometimes, I got this message when I access to volume group (lvcreate, lvdisplay ...).
Lvm command lock up in D state and I can't re-use lvm it until reboot. 

Nov  6 22:07:19 pack-xen03 kernel: [1005246.888359] INFO: task lvdisplay:8411 blocked for more than 120 seconds.
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888413] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888464] lvdisplay     D 0000000000000000     0  8411   8165 0x00000000
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888471]  ffff88007ff93f90 0000000000000286 0000000000000000 0000000000000000
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888479]  ffff880071222608 000000006c864f69 000000000000f9e0 ffff880040413fd8
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888487]  0000000000015780 0000000000015780 ffff88007c283170 ffff88007c283468
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888495] Call Trace:
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888504]  [<ffffffff8102ddc4>] ? pvclock_clocksource_read+0x3a/0x8b
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888513]  [<ffffffff8130cdda>] ? io_schedule+0x73/0xb7
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888519]  [<ffffffff81115489>] ? __blockdev_direct_IO+0x910/0xa60
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888525]  [<ffffffff81113946>] ? blkdev_direct_IO+0x45/0x4a
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888531]  [<ffffffff81112c5b>] ? blkdev_get_blocks+0x0/0x8b
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888537]  [<ffffffff810b6837>] ? generic_file_aio_read+0xf6/0x536
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888554]  [<ffffffffa01c0b05>] ? dm_blk_open+0x10/0x5f [dm_mod]
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888559]  [<ffffffff81114001>] ? __blkdev_get+0x29c/0x342
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888564]  [<ffffffff811140ae>] ? blkdev_open+0x0/0x96
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888568]  [<ffffffff81114115>] ? blkdev_open+0x67/0x96
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888575]  [<ffffffff810f00dd>] ? do_sync_read+0xce/0x113
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888580]  [<ffffffff810f342f>] ? cp_new_stat+0xe9/0xfc
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888586]  [<ffffffff81066092>] ? autoremove_wake_function+0x0/0x2e
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888591]  [<ffffffff81112ef6>] ? block_ioctl+0x38/0x3c
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888597]  [<ffffffff810fbf3e>] ? vfs_ioctl+0x21/0x6c
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888602]  [<ffffffff810fc48c>] ? do_vfs_ioctl+0x48d/0x4cb
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888608]  [<ffffffff810f0b00>] ? vfs_read+0xa6/0xff
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888613]  [<ffffffff810f0c15>] ? sys_read+0x45/0x6e
Nov  6 22:07:19 pack-xen03 kernel: [1005246.888619]  [<ffffffff81011b42>] ? system_call_fastpath+0x16/0x1b

-- System Information:
Debian Release: 6.0.5
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-5-xen-amd64 (SMP w/24 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash