Patch "ext4: fix overflow caused by missing cast in ext4_resize_fs()" has been added to the 4.12-stable tree

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

ext4: fix overflow caused by missing cast in ext4_resize_fs()

to the 4.12-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:
ext4-fix-overflow-caused-by-missing-cast-in-ext4_resize_fs.patch
and it can be found in the queue-4.12 subdirectory.

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

From: Jerry Lee <[email protected]>
Date: Sun, 6 Aug 2017 01:18:31 -0400
Subject: ext4: fix overflow caused by missing cast in ext4_resize_fs()

From: Jerry Lee <[email protected]>

commit aec51758ce10a9c847a62a48a168f8c804c6e053 upstream.

On a 32-bit platform, the value of n_blcoks_count may be wrong during the file system is resized to size larger than 2^32 blocks. This may caused the superblock being corrupted with zero blocks count.

---
 fs/ext4/resize.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -1927,7 +1927,8 @@ retry:
 			n_desc_blocks = o_desc_blocks +
 				le16_to_cpu(es->s_reserved_gdt_blocks);
 			n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
-			n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
+			n_blocks_count = (ext4_fsblk_t)n_group *
+				EXT4_BLOCKS_PER_GROUP(sb);
 			n_group--; /* set to last group number */
 		}
 

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

queue-4.12/ext4-fix-overflow-caused-by-missing-cast-in-ext4_resize_fs.patch