diff options
| author | Matthew Wilcox (Oracle) | 2024-01-16 21:29:59 +0000 |
|---|---|---|
| committer | Jens Axboe | 2024-01-16 15:02:25 -0700 |
| commit | 7bed6f3d08b7af27b7015da8dc3acf2b9c1f21d7 (patch) | |
| tree | 434bc7943d25e5b21eeaf415c4b338311a1d4bc6 /include/linux | |
| parent | be50df31c4e2a69f961a3bb759346d299eaa2b23 (diff) | |
block: Fix iterating over an empty bio with bio_for_each_folio_all
If the bio contains no data, bio_first_folio() calls page_folio() on a
NULL pointer and oopses. Move the test that we've reached the end of
the bio from bio_next_folio() to bio_first_folio().
Reported-by: syzbot+8b23309d5788a79d3eea@syzkaller.appspotmail.com
Reported-by: syzbot+004c1e0fced2b4bc3dcc@syzkaller.appspotmail.com
Fixes: 640d1930bef4 ("block: Add bio_for_each_folio_all()")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240116212959.3413014-1-willy@infradead.org
[axboe: add unlikely() to error case]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/bio.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h index ec4db73e5f4e..875d792bffff 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -286,6 +286,11 @@ static inline void bio_first_folio(struct folio_iter *fi, struct bio *bio, { struct bio_vec *bvec = bio_first_bvec_all(bio) + i; + if (unlikely(i >= bio->bi_vcnt)) { + fi->folio = NULL; + return; + } + fi->folio = page_folio(bvec->bv_page); fi->offset = bvec->bv_offset + PAGE_SIZE * (bvec->bv_page - &fi->folio->page); @@ -303,10 +308,8 @@ static inline void bio_next_folio(struct folio_iter *fi, struct bio *bio) fi->offset = 0; fi->length = min(folio_size(fi->folio), fi->_seg_count); fi->_next = folio_next(fi->folio); - } else if (fi->_i + 1 < bio->bi_vcnt) { - bio_first_folio(fi, bio, fi->_i + 1); } else { - fi->folio = NULL; + bio_first_folio(fi, bio, fi->_i + 1); } } |