Messages in this thread | | | Date | Tue, 25 Jan 2011 08:57:58 +1000 | From | Neil Brown <> | Subject | Re: Deadlock on concurrent remount-ro and mdadm --stop (2.6.37) |
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On Sun, 23 Jan 2011 17:15:00 +0100 Harald Braumann <harry@unheit.net> wrote:
> On Fri, Jan 21, 2011 at 01:47:54PM +0100, Harald Braumann wrote: > > On shutdown `umountroot' and `mdadm-raid' are executed > > concurrently. The actual commands are: > > mount -o remount,ro / > > mdadm --stop --scan > > > > This seems to trigger a deadlock in the kernel. Dumping blocked > > tasks (sysrq-W) gives: > > > > md126_raid5: call trace: > > md_super_wait > > autoremove_wake_function > > bitmap_unplug > > ... > > > > mount: call trace: > > sync_page > > io_schedule > > sync_page > > I've now disable parallel boot in my system, so umountroot and mdadm > shouldn't be called cuncurrently anymore. But I still get lock-ups on > mdadm --stop. Umountroot is called before mdadm --stop, and all other > filesystems are unmounted before that, so I guess > there should be no `sync_page' in progress anymore. But I also have > swap on the raid, so maybe there's a problem? > > As not even the magic SysRQ keys work, I can't provide any more > details. Any suggestions how I could debug this problem?
Thanks for the bug report. Extra useful details would include: cat /proc/mdstat cat /proc/mounts
i.e. what is the exact configuration of the RAID or RAIDs, and where are they mounted.
Thanks, NeilBrown
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