Commit b7aa84d9 authored Apr 08, 2014 by Martin K. Petersen Committed by Jens Axboe Apr 09, 2014

block: Fix for_each_bvec()

Commit 4550dd6c introduced for_each_bvec() which iterates over each
bvec attached to a bio or bip. However, the macro fails to check bi_size
before dereferencing which can lead to crashes while counting/mapping
integrity scatterlist segments.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Jens Axboe <axboe@fb.com>

parent 44bd70c3

include/linux/bio.h

+3 −3

Original line number	Diff line number	Diff line
		@@ -216,9 +216,9 @@ static inline void bvec_iter_advance(struct bio_vec bv, struct bvec_iter iter,
		}

		#define for_each_bvec(bvl, bio_vec, iter, start) \
		for ((iter) = start; \
		(bvl) = bvec_iter_bvec((bio_vec), (iter)), \
		(iter).bi_size; \
		for (iter = (start); \
		(iter).bi_size && \
		((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
		bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))

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