Commit 53b351f9 authored Jun 22, 2009 by Mikulas Patocka Committed by Alasdair G Kergon Jun 22, 2009

dm mpath: flush keventd queue in destructor



The commit fe9cf30e moves dm table event
submission from kmultipath queue to kernel kevent queue to avoid a
deadlock.

There is a possibility of race condition because kevent queue is not flushed
in the multipath destructor. The scenario is:
- some event happens and is queued to keventd
- keventd thread is delayed due to scheuling latency or some other work
- multipath device is destroyed
- keventd now attempts to process work_struct that is residing in already
  released memory.

The patch flushes the keventd queue in multipath constructor.
I've already fixed similar bug in dm-raid1.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: stable@kernel.org

parent a72986c5

drivers/md/dm-mpath.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -848,6 +848,7 @@ static void multipath_dtr(struct dm_target *ti)

		flush_workqueue(kmpath_handlerd);
		flush_workqueue(kmultipathd);
		flush_scheduled_work();
		free_multipath(m);
		}