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[68.103.222.6]) by smtp.gmail.com with ESMTPSA id i11sm465342otp.76.2021.03.18.06.52.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Mar 2021 06:52:24 -0700 (PDT) From: Connor Kuehl To: virtio-fs@redhat.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, stefanha@redhat.com, vgoyal@redhat.com, miklos@szeredi.hu, jasowang@redhat.com, mst@redhat.com Subject: [PATCH 1/3] virtio_ring: always warn when descriptor chain exceeds queue size Date: Thu, 18 Mar 2021 08:52:21 -0500 Message-Id: <20210318135223.1342795-2-ckuehl@redhat.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210318135223.1342795-1-ckuehl@redhat.com> References: <20210318135223.1342795-1-ckuehl@redhat.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From section 2.6.5.3.1 (Driver Requirements: Indirect Descriptors) of the virtio spec: "A driver MUST NOT create a descriptor chain longer than the Queue Size of the device." This text suggests that the warning should trigger even if indirect descriptors are in use. Reported-by: Stefan Hajnoczi Signed-off-by: Connor Kuehl --- drivers/virtio/virtio_ring.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 71e16b53e9c1..1bc290f9ba13 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -444,11 +444,12 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, head = vq->free_head; + WARN_ON_ONCE(total_sg > vq->split.vring.num); + if (virtqueue_use_indirect(_vq, total_sg)) desc = alloc_indirect_split(_vq, total_sg, gfp); else { desc = NULL; - WARN_ON_ONCE(total_sg > vq->split.vring.num && !vq->indirect); } if (desc) { @@ -1118,6 +1119,8 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, BUG_ON(total_sg == 0); + WARN_ON_ONCE(total_sg > vq->packed.vring.num); + if (virtqueue_use_indirect(_vq, total_sg)) return virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs, in_sgs, data, gfp); @@ -1125,8 +1128,6 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, head = vq->packed.next_avail_idx; avail_used_flags = vq->packed.avail_used_flags; - WARN_ON_ONCE(total_sg > vq->packed.vring.num && !vq->indirect); - desc = vq->packed.vring.desc; i = head; descs_used = total_sg;