diff options
| author | Kent Overstreet <kent.overstreet@gmail.com> | 2018-05-08 21:33:56 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-05-14 13:16:13 -0600 |
| commit | 0ba99ca4838bc75481a4bf0e70bad20b0a5457c7 (patch) | |
| tree | b39b4f4fe72a4b4ff1016a512d40998dfb1d595c | |
| parent | 6e6e811d747bfe40228dc72309450803ef74d380 (diff) | |
| download | linux-0ba99ca4838bc75481a4bf0e70bad20b0a5457c7.tar.bz2 | |
block: Add warning for bi_next not NULL in bio_endio()
Recently found a bug where a driver left bi_next not NULL and then
called bio_endio(), and then the submitter of the bio used
bio_copy_data() which was treating src and dst as lists of bios.
Fixed that bug by splitting out bio_list_copy_data(), but in case other
things are depending on bi_next in weird ways, add a warning to help
avoid more bugs like that in the future.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/bio.c | 3 | ||||
| -rw-r--r-- | block/blk-core.c | 8 |
2 files changed, 10 insertions, 1 deletions
diff --git a/block/bio.c b/block/bio.c index 2112ad01b52c..d8bcc12d5aa4 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1775,6 +1775,9 @@ again: if (!bio_integrity_endio(bio)) return; + if (WARN_ONCE(bio->bi_next, "driver left bi_next not NULL")) + bio->bi_next = NULL; + /* * Need to have a real endio function for chained bios, otherwise * various corner cases will break (like stacking block devices that diff --git a/block/blk-core.c b/block/blk-core.c index b431558f39bc..43370faee935 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -279,6 +279,10 @@ static void req_bio_endio(struct request *rq, struct bio *bio, bio_advance(bio, nbytes); /* don't actually finish bio if it's part of flush sequence */ + /* + * XXX this code looks suspicious - it's not consistent with advancing + * req->bio in caller + */ if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ)) bio_endio(bio); } @@ -3083,8 +3087,10 @@ bool blk_update_request(struct request *req, blk_status_t error, struct bio *bio = req->bio; unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); - if (bio_bytes == bio->bi_iter.bi_size) + if (bio_bytes == bio->bi_iter.bi_size) { req->bio = bio->bi_next; + bio->bi_next = NULL; + } /* Completion has already been traced */ bio_clear_flag(bio, BIO_TRACE_COMPLETION); |