Re: [PATCH v7 1/8] block: ensure bios are not split in middle of crypto data unit
From: Eric Biggers <ebiggers@kernel.org>
Date: 2020-11-25 22:15:25
Also in:
linux-ext4, linux-f2fs-devel, linux-fscrypt, linux-xfs, lkml
On Tue, Nov 17, 2020 at 02:07:01PM +0000, Satya Tangirala wrote:
quoted hunk ↗ jump to hunk
@@ -275,11 +331,24 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, bvprvp = &bvprv; } + /* + * The input bio's number of sectors is assumed to be aligned to + * bio_sectors_alignment. If that's the case, then this function should + * ensure that aligned_segs == nsegs and aligned_sectors == sectors if + * the bio is not going to be split. + */ + WARN_ON(aligned_segs != nsegs || aligned_sectors != sectors); *segs = nsegs; return NULL; split: - *segs = nsegs; - return bio_split(bio, sectors, GFP_NOIO, bs); + *segs = aligned_segs; + if (WARN_ON(aligned_sectors == 0)) + goto err; + return bio_split(bio, aligned_sectors, GFP_NOIO, bs); +err: + bio->bi_status = BLK_STS_IOERR; + bio_endio(bio); + return bio; }
[...]
quoted hunk ↗ jump to hunk
diff --git a/block/blk-mq.c b/block/blk-mq.c index 55bcee5dc032..de5c97ab8e5a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c@@ -2161,6 +2161,9 @@ blk_qc_t blk_mq_submit_bio(struct bio *bio) blk_queue_bounce(q, &bio); __blk_queue_split(&bio, &nr_segs); + if (bio->bi_status != BLK_STS_OK) + goto queue_exit; +
Note that as soon as bio_endio() is called, the bio may be freed. So accessing the bio after that is not correct. - Eric