[dm-devel] Patch "dm raid: protect md_stop() with 'reconfig_mutex'" has been added to the 5.15-stable tree

[Sasha Levin]

This is a note to let you know that I've just added the patch titled

    dm raid: protect md_stop() with 'reconfig_mutex'

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     dm-raid-protect-md_stop-with-reconfig_mutex.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.



commit 2ae858e67bfd2918d6d1f62724efc16c800fb1c3
Author: Yu Kuai <yukuai3 at huawei.com>
Date:   Sat Jul 8 17:21:53 2023 +0800

    dm raid: protect md_stop() with 'reconfig_mutex'
    
    [ Upstream commit 7d5fff8982a2199d49ec067818af7d84d4f95ca0 ]
    
    __md_stop_writes() and __md_stop() will modify many fields that are
    protected by 'reconfig_mutex', and all the callers will grab
    'reconfig_mutex' except for md_stop().
    
    Also, update md_stop() to make certain 'reconfig_mutex' is held using
    lockdep_assert_held().
    
    Fixes: 9d09e663d550 ("dm: raid456 basic support")
    Signed-off-by: Yu Kuai <yukuai3 at huawei.com>
    Signed-off-by: Mike Snitzer <snitzer at kernel.org>
    Signed-off-by: Sasha Levin <sashal at kernel.org>

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 6d4e287350a33..8d489933d5792 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3305,8 +3305,8 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	return 0;
 
 bad_unlock:
-	mddev_unlock(&rs->md);
 	md_stop(&rs->md);
+	mddev_unlock(&rs->md);
 bad:
 	raid_set_free(rs);
 
@@ -3317,7 +3317,9 @@ static void raid_dtr(struct dm_target *ti)
 {
 	struct raid_set *rs = ti->private;
 
+	mddev_lock_nointr(&rs->md);
 	md_stop(&rs->md);
+	mddev_unlock(&rs->md);
 	raid_set_free(rs);
 }
 
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5a21aeedc1ba7..89a270d293698 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6281,6 +6281,8 @@ static void __md_stop(struct mddev *mddev)
 
 void md_stop(struct mddev *mddev)
 {
+	lockdep_assert_held(&mddev->reconfig_mutex);
+
 	/* stop the array and free an attached data structures.
 	 * This is called from dm-raid
 	 */