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| author | Xinyu Zhang <xizhang@purestorage.com> | 2024-10-23 15:15:19 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-11-08 16:26:45 +0100 |
| commit | 25326b9c135d765fb660310d1c5258ac1828d6b6 (patch) | |
| tree | dda5cb8f531ed8b252deebc6d7463bc934819bdb /block | |
| parent | 58c7f44c7b9e5ac7e3b1e5da2572ed7767a12f38 (diff) | |
| download | linux-25326b9c135d765fb660310d1c5258ac1828d6b6.tar.gz linux-25326b9c135d765fb660310d1c5258ac1828d6b6.tar.bz2 linux-25326b9c135d765fb660310d1c5258ac1828d6b6.zip | |
block: fix sanity checks in blk_rq_map_user_bvec
[ Upstream commit 2ff949441802a8d076d9013c7761f63e8ae5a9bd ]
blk_rq_map_user_bvec contains a check bytes + bv->bv_len > nr_iter which
causes unnecessary failures in NVMe passthrough I/O, reproducible as
follows:
- register a 2 page, page-aligned buffer against a ring
- use that buffer to do a 1 page io_uring NVMe passthrough read
The second (i = 1) iteration of the loop in blk_rq_map_user_bvec will
then have nr_iter == 1 page, bytes == 1 page, bv->bv_len == 1 page, so
the check bytes + bv->bv_len > nr_iter will succeed, causing the I/O to
fail. This failure is unnecessary, as when the check succeeds, it means
we've checked the entire buffer that will be used by the request - i.e.
blk_rq_map_user_bvec should complete successfully. Therefore, terminate
the loop early and return successfully when the check bytes + bv->bv_len
> nr_iter succeeds.
While we're at it, also remove the check that all segments in the bvec
are single-page. While this seems to be true for all users of the
function, it doesn't appear to be required anywhere downstream.
CC: stable@vger.kernel.org
Signed-off-by: Xinyu Zhang <xizhang@purestorage.com>
Co-developed-by: Uday Shankar <ushankar@purestorage.com>
Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Fixes: 37987547932c ("block: extend functionality to map bvec iterator")
Link: https://lore.kernel.org/r/20241023211519.4177873-1-ushankar@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-map.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/block/blk-map.c b/block/blk-map.c index b337ae347bfa..a2fa38756037 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -597,9 +597,7 @@ static int blk_rq_map_user_bvec(struct request *rq, const struct iov_iter *iter) if (nsegs >= nr_segs || bytes > UINT_MAX - bv->bv_len) goto put_bio; if (bytes + bv->bv_len > nr_iter) - goto put_bio; - if (bv->bv_offset + bv->bv_len > PAGE_SIZE) - goto put_bio; + break; nsegs++; bytes += bv->bv_len; |