From: Sunwook Eom <speed.eom@samsung.com> 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@vger.kernel.org Signed-off-by: Sunwook Eom <speed.eom@samsung.com> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/md/dm-verity-fec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c index 0f4a214..bb83279 100644 --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -436,7 +436,7 @@ int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io, 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 -- 1.8.3