This bug is missing log files that will aid in diagnosing the problem.
>From a terminal window please run:
apport-collect 1598285
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable
to run this command, please add a comment stating that fact and change
the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the
Ubuntu Kernel Team.
** Changed in: linux (Ubuntu)
Status: New => Incomplete
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1598285
Title:
possible deadlock while using the cgroup freezer on a container with
NFS-based workload
Status in linux package in Ubuntu:
Incomplete
Bug description:
Hi guys,
For background: I'm running a container with an NFS filesystem bind
mounted into it. The workload I'm running is iozone, a filesystem
benchmarking tool. While running this workload, I attempt to freeze
the container, which gets stuck in the FREEZING state. After a while,
I get:
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.104156] INFO: task
iozone:20035 blocked for more than 120 seconds.
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.111056] Tainted: P
O 4.4.0-24-generic #43-Ubuntu
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.118053] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126110] iozone D
ffff880015673e18 0 20035 20005 0x00000104
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126116] ffff880015673e18
ffff880000000010 ffff880045a21b80 ffff880037776e00
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126118] ffff880015674000
ffff8800179d6e54 ffff880037776e00 00000000ffffffff
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126120] ffff8800179d6e58
ffff880015673e30 ffffffff81821b15 ffff8800179d6e50
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126121] Call Trace:
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126129] [<ffffffff81821b15>]
schedule+0x35/0x80
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126131] [<ffffffff81821dbe>]
schedule_preempt_disabled+0xe/0x10
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126134] [<ffffffff818239f9>]
__mutex_lock_slowpath+0xb9/0x130
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126136] [<ffffffff81823a8f>]
mutex_lock+0x1f/0x30
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126139] [<ffffffff8121d00b>]
do_unlinkat+0x12b/0x2d0
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126142] [<ffffffff8121dc16>]
SyS_unlink+0x16/0x20
Jul 1 01:45:14 juju-19f8e3-15 kernel: [206520.126146] [<ffffffff81825bf2>]
entry_SYSCALL_64_fastpath+0x16/0x71
It looks like the task is actually stuck in generic fs code, not
anything NFS specific, but perhaps that's a relevant detail. Anyway:
ubuntu@juju-19f8e3-15:~$ sudo cat /proc/20035/stack
[<ffffffff8121d00b>] do_unlinkat+0x12b/0x2d0
[<ffffffff8121dc16>] SyS_unlink+0x16/0x20
[<ffffffff81825bf2>] entry_SYSCALL_64_fastpath+0x16/0x71
[<ffffffffffffffff>] 0xffffffffffffffff
The container and host are both xenial:
ubuntu@juju-19f8e3-15:~$ uname -a
Linux juju-19f8e3-15 4.4.0-24-generic #43-Ubuntu SMP Wed Jun 8 19:27:37 UTC
2016 x86_64 x86_64 x86_64 GNU/Linux
Finally, I don't have a good reproducer for this. It's pretty rare, as
I'm running this benchmark in a loop, and over thousands of runs I've
seen this exactly once.
I'll leave these hosts up for a bit if there's any other interesting
bits of info to collect.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1598285/+subscriptions
--
Mailing list: https://launchpad.net/~kernel-packages
Post to : kernel-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~kernel-packages
More help : https://help.launchpad.net/ListHelp
