md: flush ->event_work before stopping array.

The 'event_work' worker used by dm-raid may still be running
when the array is stopped.  This can result in an oops.

So flush the workqueue on which it is run after detaching
and before destroying the device.

Reported-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: stable@vger.kernel.org (2.6.38+ please delay 2 weeks after -final release)
Fixes: 9d09e663d550 ("dm: raid456 basic support")

diff --git a/drivers/md/md.c b/drivers/md/md.c
index df92d30ca054c68a2af9cc3ee299525d1635a0eb..5025b3ec13cddee4796f3c12d65b9edac0e93776 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5382,6 +5382,8 @@ static void __md_stop(struct mddev *mddev)
 {
        struct md_personality *pers = mddev->pers;
        mddev_detach(mddev);
+       /* Ensure ->event_work is done */
+       flush_workqueue(md_misc_wq);
        spin_lock(&mddev->lock);
        mddev->ready = 0;
        mddev->pers = NULL;