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Mon, 06 Jul 2026 09:19:11 -0700 (PDT) Message-ID: <717fd2f3-6493-4dc5-ba83-c8d2af278639@kernel.dk> Date: Mon, 6 Jul 2026 10:19:10 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1] io_uring: fix dangling iovec after provided-buffer bundle grow failure To: Hao-Yu Yang , linux-kernel@vger.kernel.org Cc: io-uring@vger.kernel.org References: <20260705234534.768138-1-naup96721@gmail.com> Content-Language: en-US From: Jens Axboe In-Reply-To: <20260705234534.768138-1-naup96721@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/5/26 5:45 PM, Hao-Yu Yang wrote: > diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c > index 3cd29477fff2..4055173e0c48 100644 > --- a/io_uring/kbuf.c > +++ b/io_uring/kbuf.c > @@ -256,6 +256,7 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg, > struct io_uring_buf_ring *br = bl->buf_ring; > struct iovec *org_iovs = arg->iovs; > struct iovec *iov = arg->iovs; > + struct iovec *old = NULL; > int nr_iovs = arg->nr_iovs; > __u16 nr_avail, tail, head; > struct io_uring_buf *buf; > @@ -288,7 +289,7 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg, > if (unlikely(!iov)) > return -ENOMEM; > if (arg->mode & KBUF_MODE_FREE) > - kfree(arg->iovs); > + old = arg->iovs; > arg->iovs = iov; > nr_iovs = nr_avail; > } else if (nr_avail < nr_iovs) { > @@ -318,6 +319,8 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg, > if (unlikely(!access_ok(iov->iov_base, len))) { > if (arg->iovs != org_iovs) > kfree(arg->iovs); > + /* hand the still-live cached vec back to the owner */ > + arg->iovs = org_iovs; > return -EFAULT; > } > iov++; > @@ -330,6 +333,8 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg, > buf = io_ring_head_to_buf(br, ++head, bl->mask); > } while (--nr_iovs); > > + kfree(old); > + > if (head == tail) > req->flags |= REQ_F_BL_EMPTY; Can't we just do the below, that seems a lot simpler? diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index 3cd29477fff2..3bb24d20c890 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -287,8 +287,6 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg, iov = kmalloc_objs(struct iovec, nr_avail); if (unlikely(!iov)) return -ENOMEM; - if (arg->mode & KBUF_MODE_FREE) - kfree(arg->iovs); arg->iovs = iov; nr_iovs = nr_avail; } else if (nr_avail < nr_iovs) { @@ -330,6 +328,9 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg, buf = io_ring_head_to_buf(br, ++head, bl->mask); } while (--nr_iovs); + if (arg->mode & KBUF_MODE_FREE) + kfree(org_iovs); + if (head == tail) req->flags |= REQ_F_BL_EMPTY; -- Jens Axboe