From: Mikulas Patocka Date: Mon, 26 Aug 2019 06:41:17 +0000 (-0400) Subject: dm zoned: fix invalid memory access X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0c8e9c2d668278652af028c3cc068c65f66342f4;p=linux.git dm zoned: fix invalid memory access Commit 75d66ffb48efb30f2dd42f041ba8b39c5b2bd115 ("dm zoned: properly handle backing device failure") triggers a coverity warning: *** CID 1452808: Memory - illegal accesses (USE_AFTER_FREE) /drivers/md/dm-zoned-target.c: 137 in dmz_submit_bio() 131 clone->bi_private = bioctx; 132 133 bio_advance(bio, clone->bi_iter.bi_size); 134 135 refcount_inc(&bioctx->ref); 136 generic_make_request(clone); >>> CID 1452808: Memory - illegal accesses (USE_AFTER_FREE) >>> Dereferencing freed pointer "clone". 137 if (clone->bi_status == BLK_STS_IOERR) 138 return -EIO; 139 140 if (bio_op(bio) == REQ_OP_WRITE && dmz_is_seq(zone)) 141 zone->wp_block += nr_blocks; 142 The "clone" bio may be processed and freed before the check "clone->bi_status == BLK_STS_IOERR" - so this check can access invalid memory. Fixes: 75d66ffb48efb3 ("dm zoned: properly handle backing device failure") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Reviewed-by: Damien Le Moal Signed-off-by: Mike Snitzer --- diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c index 31478fef6032d..d3bcc4197f5dd 100644 --- a/drivers/md/dm-zoned-target.c +++ b/drivers/md/dm-zoned-target.c @@ -134,8 +134,6 @@ static int dmz_submit_bio(struct dmz_target *dmz, struct dm_zone *zone, refcount_inc(&bioctx->ref); generic_make_request(clone); - if (clone->bi_status == BLK_STS_IOERR) - return -EIO; if (bio_op(bio) == REQ_OP_WRITE && dmz_is_seq(zone)) zone->wp_block += nr_blocks;