Commit 69e0927b authored Jan 14, 2018 by Douglas Gilbert Committed by Jens Axboe Jan 15, 2018

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 <dgilbert@interlog.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent fa70d2e2

block/blk-map.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -114,7 +114,7 @@ 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;
		@@ -143,7 +143,7 @@ unmap_rq:
		__blk_rq_unmap_user(bio);
		fail:
		rq->bio = NULL;
		return -EINVAL;
		return ret;
		}
		EXPORT_SYMBOL(blk_rq_map_user_iov);

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