Hi Min, > -----Original Message----- > From: Min Zhou <zhou...@loongson.cn> > Sent: Monday, August 29, 2022 4:29 PM > To: david.march...@redhat.com; maxime.coque...@redhat.com; Xia, Chenbo > <chenbo....@intel.com>; zhou...@loongson.cn > Cc: dev@dpdk.org; maob...@loongson.cn > Subject: [PATCH v2] vhost: fix build > > 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(-)
Just want you to know that your patch is still pending because by accident your fix is almost the same as a previous patch that fixes a real issue but that patch is still in progress: http://patchwork.dpdk.org/project/dpdk/patch/20220802004938.23670-2-cfont...@suse.de/ Thanks, Chenbo > > 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; > -- > 2.31.1
