From: Keith Busch Date: Mon, 20 Nov 2023 22:18:31 +0000 (-0800) Subject: io_uring: fix off-by one bvec index X-Git-Tag: v5.15.141~1 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=313a34d1c0ee40d15f098e267f2824bd178d39ea;p=thirdparty%2Fkernel%2Fstable.git io_uring: fix off-by one bvec index commit d6fef34ee4d102be448146f24caf96d7b4a05401 upstream. If the offset equals the bv_len of the first registered bvec, then the request does not include any of that first bvec. Skip it so that drivers don't have to deal with a zero length bvec, which was observed to break NVMe's PRP list creation. Cc: stable@vger.kernel.org Fixes: bd11b3a391e3 ("io_uring: don't use iov_iter_advance() for fixed buffers") Signed-off-by: Keith Busch Link: https://lore.kernel.org/r/20231120221831.2646460-1-kbusch@meta.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 4852e8579df5d..5b2dbd3dc2deb 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3152,7 +3152,7 @@ static int __io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter */ const struct bio_vec *bvec = imu->bvec; - if (offset <= bvec->bv_len) { + if (offset < bvec->bv_len) { iov_iter_advance(iter, offset); } else { unsigned long seg_skip;