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blk_rq_map_user_iov: fix error override

PATCH Applied Douglas Gilbert 2 participants 2 messages Jan 14, 2018 – Jan 15, 2018

Subsystems (2)
SCSI Block layer
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Douglas Gilbert

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#0 lore raw

PATCH 1/1 blk_rq_map_user_iov: fix error override

During stress tests by syzkaller on the sg driver the block layer infrequently returns EINVAL. Closer inspection shows the block layer was trying to return ENOMEM (which is much more understandable) but for some reason overroad that useful error.

Patch below does not show this (unchanged) line:
ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy);
That 'ret' was being overridden when that function failed.

Signed-off-by Douglas Gilbert <[email protected]>
---
 block/blk-map.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
block/blk-map.c +2 -2
index d3a94719f03f..db9373bd31ac 100644
@@ -119,7 +119,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 	unsigned long align = q->dma_pad_mask | queue_dma_alignment(q);
 	struct bio *bio = NULL;
 	struct iov_iter i;
-	int ret;
+	int ret = -EINVAL;
 
 	if (!iter_is_iovec(iter))
 		goto fail;

@@ -148,7 +148,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 	__blk_rq_unmap_user(bio);
 fail:
 	rq->bio = NULL;
-	return -EINVAL;
+	return ret;
 }
 EXPORT_SYMBOL(blk_rq_map_user_iov);
Signature · 1 line
2.14.1
maintainer Applied
#1 lore raw
Quoted 8 lines · Douglas Gilbert

During stress tests by syzkaller on the sg driver the block layer infrequently returns EINVAL. Closer inspection shows the block layer was trying to return ENOMEM (which is much more understandable) but for some reason overroad that useful error.

Patch below does not show this (unchanged) line:

   ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy);

That 'ret' was being overridden when that function failed.

Thanks, applied.

Signature · 1 line
Jens Axboe