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FAILED: patch "[PATCH] dm raid: fix KASAN warning in raid5_remove_disk" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Jul 4, 2022

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The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1ebc2cec0b7dd8dad0812449110803bd875ac816 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <[email protected]>
Date: Wed, 29 Jun 2022 13:40:01 -0400
Subject: [PATCH] dm raid: fix KASAN warning in raid5_remove_disk

There's a KASAN warning in raid5_remove_disk when running the LVM testsuite. We fix this warning by verifying that the "number" variable is within limits.

Cc [email protected]
Signed-off-by Mikulas Patocka <[email protected]>
Signed-off-by Mike Snitzer <[email protected]>
drivers/md/raid5.c +4 -1
index 5d09256d7f81..ba289411f26f 100644
@@ -7933,7 +7933,7 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
 	int err = 0;
 	int number = rdev->raid_disk;
 	struct md_rdev __rcu **rdevp;
-	struct disk_info *p = conf->disks + number;
+	struct disk_info *p;
 	struct md_rdev *tmp;
 
 	print_raid5_conf(conf);

@@ -7952,6 +7952,9 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
 		log_exit(conf);
 		return 0;
 	}
+	if (unlikely(number >= conf->pool_size))
+		return 0;
+	p = conf->disks + number;
 	if (rdev == rcu_access_pointer(p->rdev))
 		rdevp = &p->rdev;
 	else if (rdev == rcu_access_pointer(p->replacement))