From: Kent Overstreet kent.overstreet@linux.dev
[ Upstream commit 168145f617d57bf4e474901b7ffa869337a802e6 ]
bio_iov_iter_get_pages() trims the IO based on the block size of the block device the IO will be issued to.
However, bcachefs is a multi device filesystem; when we're creating the bio we don't yet know which block device the bio will be submitted to - we have to handle the alignment checks elsewhere.
Thus this is needed to avoid a null ptr deref.
Signed-off-by: Kent Overstreet kent.overstreet@linux.dev Cc: Jens Axboe axboe@kernel.dk Cc: linux-block@vger.kernel.org Link: https://lore.kernel.org/r/20230813182636.2966159-3-kent.overstreet@linux.dev Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/bio.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/block/bio.c b/block/bio.c index 043944fd46ebb..e54f2a9cbf9ba 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1245,7 +1245,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) struct page **pages = (struct page **)bv; ssize_t size, left; unsigned len, i = 0; - size_t offset, trim; + size_t offset; int ret = 0;
/* @@ -1274,10 +1274,12 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE);
- trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1); - iov_iter_revert(iter, trim); + if (bio->bi_bdev) { + size_t trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1); + iov_iter_revert(iter, trim); + size -= trim; + }
- size -= trim; if (unlikely(!size)) { ret = -EFAULT; goto out;