md: flush ->event_work before stopping array.

commit ee5d004fd0591536a061451eba2b187092e9127c upstream.

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>
Fixes: 9d09e663d550 ("dm: raid456 basic support")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2ffd277eb31193a69a10467da12f110bfd65431e..31d14d88205b4f7c5f816fdb7d41bf56c9507547 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5285,6 +5285,8 @@ EXPORT_SYMBOL_GPL(md_stop_writes);
 static void __md_stop(struct mddev *mddev)
 {
        mddev->ready = 0;
+       /* Ensure ->event_work is done */
+       flush_workqueue(md_misc_wq);
        mddev->pers->stop(mddev);
        if (mddev->pers->sync_request && mddev->to_remove == NULL)
                mddev->to_remove = &md_redundancy_group;