| Message ID | 20190219030819.16578-1-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: avoid to READ fields of null bio | expand |
diff --git a/block/blk-merge.c b/block/blk-merge.c index bed065904677..066b66430523 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -363,13 +363,15 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, struct bio_vec bv, bvprv = { NULL }; int prev = 0; unsigned int seg_size, nr_phys_segs; - unsigned front_seg_size = bio->bi_seg_front_size; + unsigned front_seg_size; struct bio *fbio, *bbio; struct bvec_iter iter; if (!bio) return 0; + front_seg_size = bio->bi_seg_front_size; + switch (bio_op(bio)) { case REQ_OP_DISCARD: case REQ_OP_SECURE_ERASE:
rq->bio can be NULL sometimes, such as flush request, so don't read bio->bi_seg_front_size until this 'bio' is checked as valid. Cc: Bart Van Assche <bvanassche@acm.org> Reported-by: Bart Van Assche <bvanassche@acm.org> Fixes: dcebd755926b0f39dd1e ("block: use bio_for_each_bvec() to compute multi-page bvec count") Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-merge.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)