Re: [f2fs-dev] 100% system time hang with git f2fs

[Marc L. <sc...@sc...>]

On Thu, Oct 01, 2015 at 08:51:24PM +0200, Marc Lehmann <sc...@sc...> wrote:
> Ok, for completeness, here is the full log and a description of what was
> going on.

Ok, so I did a fsck, which took one hour, which is not very good, but I
don't use fsck very often. It didn't find any problems (everything Ok).

However, I have a freeze. When I mount the volume, start a du on it, and after
a while do:

   echo 3 >/proc/sys/vm/drop_caches

Then this process hangs with 100% sys time. /proc/../stack gives no usable
backtrace.

umount on the f2fs volume also hangs:

   [<ffffffff8139ba03>] call_rwsem_down_write_failed+0x13/0x20
   [<ffffffff8118086d>] unregister_shrinker+0x1d/0x70
   [<ffffffff811e7911>] deactivate_locked_super+0x41/0x60
   [<ffffffff811e7eee>] deactivate_super+0x4e/0x70
   [<ffffffff81204733>] cleanup_mnt+0x43/0x90
   [<ffffffff812047d2>] __cleanup_mnt+0x12/0x20
   [<ffffffff8108e8a4>] task_work_run+0xc4/0xe0
   [<ffffffff81012fa7>] do_notify_resume+0x97/0xb0
   [<ffffffff8178896f>] int_signal+0x12/0x17
   [<ffffffffffffffff>] 0xffffffffffffffff

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