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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Mikulas Patocka <mpatocka@redhat.com>,
        Mike Snitzer <snitzer@kernel.org>
Subject: [PATCH 4.9 01/29] dm raid: fix KASAN warning in raid5_add_disks
Date:   Tue,  5 Jul 2022 13:57:42 +0200
Message-Id: <20220705115605.787481910@linuxfoundation.org>
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From: Mikulas Patocka <mpatocka@redhat.com>

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>
---
 drivers/md/raid5.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7322,6 +7322,7 @@ static int raid5_add_disk(struct mddev *
 	 */
 	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;