On Wed, Oct 5, 2022 at 4:49 PM Maxime Coquelin
<maxime.coque...@redhat.com> wrote:
>
> This patch fixes a compilation issue met with GCC on
GCC 12 (it is worth detailing, since I and Thomas hit the same issue
on some other cross compiling toolchains using GCC 12).
> Loongarch64:
LoongArch64
>
> In function ‘mbuf_to_desc’,
> inlined from ‘vhost_enqueue_async_packed’ at
> ../../../dpdk/lib/vhost/virtio_net.c:1822:6,
> inlined from ‘virtio_dev_rx_async_packed’ at
> ../../../dpdk/lib/vhost/virtio_net.c:1836:6,
> inlined from ‘virtio_dev_rx_async_submit_packed’ at
> ../../../dpdk/lib/vhost/virtio_net.c:1895:7:
> ../../../dpdk/lib/vhost/virtio_net.c:1159:18: error: ‘buf_vec[0].buf_addr’
> may be used uninitialized [-Werror=maybe-uninitialized]
> 1159 | buf_addr = buf_vec[vec_idx].buf_addr;
> | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../../../dpdk/lib/vhost/virtio_net.c: In function
> ‘virtio_dev_rx_async_submit_packed’:
> ../../../dpdk/lib/vhost/virtio_net.c:1834:27: note: ‘buf_vec’ declared here
> 1834 | struct buf_vector buf_vec[BUF_VECTOR_MAX];
> | ^~~~~~~
>
> It happens because the compiler assumes that 'size'
> variable in vhost_enqueue_async_packed could wrap to 0 since
> 'size' is uint32_t and pkt->pkt_len too.
>
> In practice, it would never happen since 'pkt->pkt_len' is
> unlikely to be close to UINT32_MAX, but let's just change
> 'size' to uint64_t to make the compiler happy without
> having to add runtime checks.
>
> Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
Reviewed-by: David Marchand <david.march...@redhat.com>
--
David Marchand
