Commit 2f6cfd6d7cb1 for kernel

commit 2f6cfd6d7cb165a7af8877b838a9f6aab4159324
Author: Alexey Simakov <bigalex934@gmail.com>
Date:   Tue Dec 2 20:18:38 2025 +0300

    dm-raid: fix possible NULL dereference with undefined raid type

    rs->raid_type is assigned from get_raid_type_by_ll(), which may return
    NULL. This NULL value could be dereferenced later in the condition
    'if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)))'.

    Add a fail-fast check to return early with an error if raid_type is NULL,
    similar to other uses of this function.

    Found by Linux Verification Center (linuxtesting.org) with Svace.

    Fixes: 33e53f06850f ("dm raid: introduce extended superblock and new raid types to support takeover/reshaping")
    Signed-off-by: Alexey Simakov <bigalex934@gmail.com>
    Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index c6f7129e43d3..4bacdc499984 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -2287,6 +2287,8 @@ static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)

 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
+			if (!rs->raid_type)
+				return -EINVAL;
 		}

 	} else {