Comment 21 for bug 624877

I don't think this has to do with heavy disk activity - I had nothing intensive running, and still don't. dpkg itself is certainly generating zero activity.

This has happened to me twice now, on my Ubuntu 10.04 64 Desktop. Not only can't I sudo pkill -9 dpkg, I can't shut down the machine; I have to power cycle the box. For me, the dpkg command is:

/usr/bin/dpkg --status-fd 46 --unpack --auto-deconfigure /var/cache/apt/archives/google-chrome-unstable_11.0.672.2-r75134_amd64.deb

Things gets stuck on....

$ sudo aptitude full-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
The following packages will be upgraded:
  google-chrome-unstable
1 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B/21.5MB of archives. After unpacking 324kB will be used.
Do you want to continue? [Y/n/?]
Writing extended state information... Done
(Reading database ... 364642 files and directories currently installed.)
Preparing to replace google-chrome-unstable 10.0.648.82-r75062 (using .../google-chrome-unstable_11.0.672.2-r75134_amd64.deb) ...
Unpacking replacement google-chrome-unstable ...

From my dmesg:

[196682.170113] INFO: task dpkg:15510 blocked for more than 120 seconds.
[196682.170119] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[196682.170123] dpkg D 0000000000000000 0 15510 15496 0x00000000
[196682.170132] ffff8800261d7e30 0000000000000082 0000000000015bc0 0000000000015bc0
[196682.170140] ffff880067f483b8 ffff8800261d7fd8 0000000000015bc0 ffff880067f48000
[196682.170147] 0000000000015bc0 ffff8800261d7fd8 0000000000015bc0 ffff880067f483b8
[196682.170154] Call Trace:
[196682.170168] [<ffffffff81544a55>] rwsem_down_failed_common+0x95/0x1f0
[196682.170174] [<ffffffff81544c06>] rwsem_down_read_failed+0x26/0x30
[196682.170182] [<ffffffff812bdc34>] call_rwsem_down_read_failed+0x14/0x30
[196682.170188] [<ffffffff81543ec4>] ? down_read+0x24/0x30
[196682.170194] [<ffffffff8116b117>] sync_filesystems+0xb7/0x130
[196682.170200] [<ffffffff8116b1e7>] sys_sync+0x17/0x40
[196682.170207] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
[196802.170737] INFO: task dpkg:15510 blocked for more than 120 seconds.
[196802.170743] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[196802.170747] dpkg D 0000000000000000 0 15510 15496 0x00000000
[196802.170755] ffff8800261d7e30 0000000000000082 0000000000015bc0 0000000000015bc0
[196802.170763] ffff880067f483b8 ffff8800261d7fd8 0000000000015bc0 ffff880067f48000
[196802.170770] 0000000000015bc0 ffff8800261d7fd8 0000000000015bc0 ffff880067f483b8
[196802.170777] Call Trace:
[196802.170791] [<ffffffff81544a55>] rwsem_down_failed_common+0x95/0x1f0
[196802.170798] [<ffffffff81544c06>] rwsem_down_read_failed+0x26/0x30
[196802.170806] [<ffffffff812bdc34>] call_rwsem_down_read_failed+0x14/0x30
[196802.170812] [<ffffffff81543ec4>] ? down_read+0x24/0x30
[196802.170819] [<ffffffff8116b117>] sync_filesystems+0xb7/0x130
[196802.170824] [<ffffffff8116b1e7>] sys_sync+0x17/0x40
[196802.170831] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b

rm-ing the lock files, sudo dpkg --configure -a, and retrying ends up with the same problem, except now I have *two* stuck dpkg processes.

I also wish that duplicates would have their "This affects me too" counts aggregated into this bug, so as to heighten the priority of this bug.