dm-raid: fix lockdep waring in "pers->hot_add_disk"

The lockdep assert is added by commit a448af25becf ("md/raid10: remove
rcu protection to access rdev from conf") in print_conf(). And I didn't
notice that dm-raid is calling "pers->hot_add_disk" without holding
'reconfig_mutex'.

"pers->hot_add_disk" read and write many fields that is protected by
'reconfig_mutex', and raid_resume() already grab the lock in other
contex. Hence fix this problem by protecting "pers->host_add_disk"
with the lock.

Fixes: 9092c02d9435 ("DM RAID: Add ability to restore transiently failed devices on resume")
Fixes: a448af25becf ("md/raid10: remove rcu protection to access rdev from conf")
Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Xiao Ni <xni@redhat.com>
Acked-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240305072306.2562024-10-yukuai1@huaweicloud.com

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index ea45f77..17e9af6 100644 (file)
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -4091,7 +4091,9 @@ static void raid_resume(struct dm_target *ti)
                 * Take this opportunity to check whether any failed
                 * devices are reachable again.
                 */
+               mddev_lock_nointr(mddev);
                attempt_restore_of_faulty_devices(rs);
+               mddev_unlock(mddev);
        }
 
        if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {