From: Pavel Begunkov Date: Tue, 24 Jun 2025 13:40:35 +0000 (+0100) Subject: io_uring: don't assume uaddr alignment in io_vec_fill_bvec X-Git-Tag: io_uring-6.16-20250626~3 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=e1d7727b73a1f78035316ac35ee184d477059f0b;p=linux-2.6-block.git io_uring: don't assume uaddr alignment in io_vec_fill_bvec There is no guaranteed alignment for user pointers. Don't use mask trickery and adjust the offset by bv_offset. Cc: stable@vger.kernel.org Reported-by: David Hildenbrand Fixes: 9ef4cbbcb4ac3 ("io_uring: add infra for importing vectored reg buffers") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/io-uring/19530391f5c361a026ac9b401ff8e123bde55d98.1750771718.git.asml.silence@gmail.com/ Signed-off-by: Jens Axboe --- diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index afc67530f912..f2b31fb68992 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -1339,7 +1339,6 @@ static int io_vec_fill_bvec(int ddir, struct iov_iter *iter, { unsigned long folio_size = 1 << imu->folio_shift; unsigned long folio_mask = folio_size - 1; - u64 folio_addr = imu->ubuf & ~folio_mask; struct bio_vec *res_bvec = vec->bvec; size_t total_len = 0; unsigned bvec_idx = 0; @@ -1361,8 +1360,13 @@ static int io_vec_fill_bvec(int ddir, struct iov_iter *iter, if (unlikely(check_add_overflow(total_len, iov_len, &total_len))) return -EOVERFLOW; - /* by using folio address it also accounts for bvec offset */ - offset = buf_addr - folio_addr; + offset = buf_addr - imu->ubuf; + /* + * Only the first bvec can have non zero bv_offset, account it + * here and work with full folios below. + */ + offset += imu->bvec[0].bv_offset; + src_bvec = imu->bvec + (offset >> imu->folio_shift); offset &= folio_mask;