This is a note to let you know that I've just added the patch titled dm verity fec: fix hash block number in verity_fec_decode to the 4.9-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-verity-fec-fix-hash-block-number-in-verity_fec_decode.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ad4e80a639fc61d5ecebb03caa5cdbfb91fcebfc Mon Sep 17 00:00:00 2001 From: Sunwook Eom <speed.eom@xxxxxxxxxxx> Date: Fri, 10 Apr 2020 12:54:19 +0900 Subject: dm verity fec: fix hash block number in verity_fec_decode From: Sunwook Eom <speed.eom@xxxxxxxxxxx> commit ad4e80a639fc61d5ecebb03caa5cdbfb91fcebfc upstream. The error correction data is computed as if data and hash blocks were concatenated. But hash block number starts from v->hash_start. So, we have to calculate hash block number based on that. Fixes: a739ff3f543af ("dm verity: add support for forward error correction") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Sunwook Eom <speed.eom@xxxxxxxxxxx> Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm-verity-fec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -447,7 +447,7 @@ int verity_fec_decode(struct dm_verity * fio->level++; if (type == DM_VERITY_BLOCK_TYPE_METADATA) - block += v->data_blocks; + block = block - v->hash_start + v->data_blocks; /* * For RS(M, N), the continuous FEC data is divided into blocks of N Patches currently in stable-queue which might be from speed.eom@xxxxxxxxxxx are queue-4.9/dm-verity-fec-fix-hash-block-number-in-verity_fec_decode.patch