bch_generic_make_request_hack() tries to be smart, and fake a bi_max_bvecs = bi_vcnt. If those bios have been REQ_DISCARD, and get submitted to a driver (md raid) that uses bio_clone, the clone will end up with bi_io_vec == NULL, passed down the stack, end up in sd_prep_fn and blk_add_request_payload, which then tries to use bio->bi_io_vec->page. Fix: try to be even smarter in bch_generic_make_request_hack(), and always pretend to have at least bi_max_vecs of 1, unless the incoming bio was already created without a single bvec. Signed-off-by: Lars Ellenberg <lars@xxxxxxxxxx> --- drivers/md/bcache/io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c index 9056632..a638ac6 100644 --- a/drivers/md/bcache/io.c +++ b/drivers/md/bcache/io.c @@ -47,7 +47,7 @@ static void bch_generic_make_request_hack(struct bio *bio) * * To be taken out once immutable bvec stuff is in. */ - bio->bi_max_vecs = bio->bi_vcnt; + bio->bi_max_vecs = bio->bi_vcnt ?: (bio->bi_io_vec ? 1 : 0); generic_make_request(bio); } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
