On 9/11/2017 4:13 PM, Olivier Matz wrote:
> The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following
> error:
>
> CC virtio_rxtx.o
> virtio_rxtx.c: In function ‘virtio_rx_offload’:
> virtio_rxtx.c:680:10: error: ‘csum’ may be used uninitialized in
> this function [-Werror=maybe-uninitialized]
> csum = ~csum;
> ~~~~~^~~~~~~
>
> The function rte_raw_cksum_mbuf() may indeed return an error, and
> in this case, csum won't be initialized. Fix it by initializing csum
> to 0.
After this fix if rte_raw_cksum_mbuf() returns error csum still will be
wrong and since compiler warning suppressed it may be harder to find the
root cause.
For this case checking rte_raw_cksum_mbuf() return value seems better
idea but I will cc the maintainer for decision.
>
> Fixes: 96cb6711939e ("net/virtio: support Rx checksum offload")
> Signed-off-by: Olivier Matz <olivier.m...@6wind.com>
> ---
> drivers/net/virtio/virtio_rxtx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> index 45a9c919a..cab3a1675 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -671,7 +671,7 @@ virtio_rx_offload(struct rte_mbuf *m, struct
> virtio_net_hdr *hdr)
> * In case of SCTP, this will be wrong since it's a CRC
> * but there's nothing we can do.
> */
> - uint16_t csum, off;
> + uint16_t csum = 0, off;
>
> rte_raw_cksum_mbuf(m, hdr->csum_start,
> rte_pktmbuf_pkt_len(m) - hdr->csum_start,
>
