dm raid: fix KASAN warning in raid5_add_disks

commit 617b365872a247480e9dcd50a32c8d1806b21861 upstream.

There's a KASAN warning in raid5_add_disk when running the LVM testsuite.
The warning happens in the test
lvconvert-raid-reshape-linear_to_raid6-single-type.sh. We fix the warning
by verifying that rdev->saved_raid_disk is within limits.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e54d802..b58984d 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -8026,6 +8026,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
         */
        if (rdev->saved_raid_disk >= 0 &&
            rdev->saved_raid_disk >= first &&
+           rdev->saved_raid_disk <= last &&
            conf->disks[rdev->saved_raid_disk].rdev == NULL)
                first = rdev->saved_raid_disk;