The patch 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.
Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
---
drivers/md/dm-zoned-target.c | 2 --
1 file changed, 2 deletions(-)
Index: linux-2.6/drivers/md/dm-zoned-target.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-zoned-target.c 2019-08-26 08:30:30.000000000
+0200
+++ linux-2.6/drivers/md/dm-zoned-target.c 2019-08-26 08:36:23.000000000
+0200
@@ -134,8 +134,6 @@ static int dmz_submit_bio(struct dmz_tar
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;
--
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