Hello everyone, I've encountered what looks like a nasty bug which occures when the OOM kills a process and that this process is working with the file system. I've been able to reproduce this issue using docker, by limiting the memory limits of process and make them crash when working.
(You can find more information there: my post on Docker bug tracker, but it seems that it is more a BTRF-related issue https://github.com/docker/docker/issues/15654#issuecomment-132384763) Once the processes have been killed, a BTRFS kworker switched in uninterruptible (state D) IO wait, and the file system is completely unusable, no way to read or write from it which is pretty critical, in my case Docker is not usable anymore as btrfs is the used storage backend. OOM logs: http://pastebin.com/Lb4Gybay (Simple OOM logs) BTRFS freeze and uninterruptible processes (plus Sysrq-w): http://pastebin.com/qd1yB8u2 Hoping that I've got enough information, tell me if you need more. Now I'm able to reproduce quite easily. Thank you, -- Leo Unbekandt @Soulou ~# uname -a Linux <hostname> 3.19.0-26-generic #28~14.04.1-Ubuntu SMP Wed Aug 12 14:09:17 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux ~# btrfs --version Btrfs v3.12 ~# btrfs fi show Label: none uuid: c36b7b1d-910e-4af7-b671-b6d437c4b8d5 Total devices 1 FS bytes used 34.03GiB devid 1 size 100.00GiB used 44.04GiB path /dev/dm-0 btrBtrfs v3.12 ~# btrfs fi df /var/lib/docker Data, single: total=35.01GiB, used=31.77GiB System, DUP: total=8.00MiB, used=16.00KiB System, single: total=4.00MiB, used=0.00 Metadata, DUP: total=4.50GiB, used=2.25GiB Metadata, single: total=8.00MiB, used=0.00 unknown, single: total=512.00MiB, used=0.00 ~# dmesg.log http://pastebin.com/S5DvJjxQ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
