Patch "dm raid: fix panic when attempting to force a raid to sync" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

dm raid: fix panic when attempting to force a raid to sync

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
dm-raid-fix-panic-when-attempting-to-force-a-raid-to-sync.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Heinz Mauelshagen <[email protected]>
Date: Thu, 2 Nov 2017 19:58:28 +0100
Subject: dm raid: fix panic when attempting to force a raid to sync

From: Heinz Mauelshagen <[email protected]>

[ Upstream commit 233978449074ca7e45d9c959f9ec612d1b852893 ]

Requesting a sync on an active raid device via a table reload (see 'sync' parameter in Documentation/device-mapper/dm-raid.txt) skips the super_load() call that defines the superblock size (rdev->sb_size) -- resulting in an oops if/when super_sync()->memset() is called.

Fix by moving the initialization of the superblock start and size out of super_load() to the caller (analyse_superblocks).

---
 drivers/md/dm-raid.c |   21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

@@ -2143,13 +2143,6 @@ static int super_load(struct md_rdev *rd
 	struct dm_raid_superblock *refsb;
 	uint64_t events_sb, events_refsb;
 
-	rdev->sb_start = 0;
-	rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
-	if (rdev->sb_size < sizeof(*sb) || rdev->sb_size > PAGE_SIZE) {
-		DMERR("superblock size of a logical block is no longer valid");
-		return -EINVAL;
-	}
-
 	r = read_disk_sb(rdev, rdev->sb_size, false);
 	if (r)
 		return r;

@@ -2494,6 +2487,17 @@ static int analyse_superblocks(struct dm
 		if (test_bit(Journal, &rdev->flags))
 			continue;
 
+		if (!rdev->meta_bdev)
+			continue;
+
+		/* Set superblock offset/size for metadata device. */
+		rdev->sb_start = 0;
+		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
+		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
+			DMERR("superblock size of a logical block is no longer valid");
+			return -EINVAL;
+		}
+
 		/*
 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
 		 * the array to undergo initialization again as

@@ -2506,9 +2510,6 @@ static int analyse_superblocks(struct dm
 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
 			continue;
 
-		if (!rdev->meta_bdev)
-			continue;
-
 		r = super_load(rdev, freshest);
 
 		switch (r) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/dm-raid-fix-panic-when-attempting-to-force-a-raid-to-sync.patch