Kindly ping. Any feedback is appreciated.
On 2022年08月29日 16:29, Min Zhou wrote:
On CentOS 8 or Debian 10.4 systems using gcc 12.1 to cross compile DPDK, gcc shows a following warning which will cause build to fail when build is run with -werror: In function 'mbuf_to_desc', inlined from 'vhost_enqueue_async_packed' at ../lib/vhost/virtio_net.c:1826:6, inlined from 'virtio_dev_rx_async_packed' at ../lib/vhost/virtio_net.c:1840:6, inlined from 'virtio_dev_rx_async_submit_packed.constprop' at ../lib/vhost/virtio_net.c:1900:7: ../lib/vhost/virtio_net.c:1161:35: error: 'buf_vec[0].buf_len' may be used uninitialized [-Werror=maybe-uninitialized] 1161 | buf_len = buf_vec[vec_idx].buf_len; | ~~~~~~~~~~~~~~~~^~~~~~~~ ../lib/vhost/virtio_net.c: In function 'virtio_dev_rx_async_submit_packed.constprop': ../lib/vhost/virtio_net.c:1838:27: note: 'buf_vec' declared here 1838 | struct buf_vector buf_vec[BUF_VECTOR_MAX]; | ^~~~~~~ cc1: all warnings being treated as errors Actually, there are eight places to see the same codes in the file lib/vhost/virtio_net.c, and all these `buf_vec` arraies are initialized by sub-function calls under various conditions. Although It's hard to understand why gcc just emits warning at one of the eight places, adding validity checks for array length is reasonable and can also fix the warning. Signed-off-by: David Marchand <david.march...@redhat.com> Signed-off-by: Min Zhou <zhou...@loongson.cn> --- lib/vhost/virtio_net.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index 35fa4670fd..99233f1759 100644 --- a/lib/vhost/virtio_net.c +++ b/lib/vhost/virtio_net.c @@ -1153,7 +1153,7 @@ mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq, struct virtio_net_hdr_mrg_rxbuf tmp_hdr, *hdr = NULL; struct vhost_async *async = vq->async;- if (unlikely(m == NULL))+ if (unlikely(m == NULL || nr_vec == 0)) return -1;buf_addr = buf_vec[vec_idx].buf_addr;@@ -2673,6 +2673,9 @@ desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, struct vhost_async *async = vq->async; struct async_inflight_info *pkts_info;+ if (unlikely(nr_vec == 0))+ return -1; + buf_addr = buf_vec[vec_idx].buf_addr; buf_iova = buf_vec[vec_idx].buf_iova; buf_len = buf_vec[vec_idx].buf_len;
