+Jason +Dmitry
On 1/14/21 8:07 AM, Miroslav Rezanina wrote:
> When building qemu with GCC 11, compiling eth.c file produce following
> warning:
>
> warning: array subscript 'struct ip6_ext_hdr_routing[0]' is partly outside
> array bounds of 'struct ip6_ext_hdr[1]' [-Warray-bounds]
>
> This is caused by retyping from ip6_ext_hdr to ip6_ext_hdr_routing that has
> more
> attributes.
>
> As this usage is expected, suppress the warning temporarily through the
> function
> using this retyping.
This is not expected, this is a bug...
>
> Signed-off-by: Miroslav Rezanina <mreza...@redhat.com>
> ---
> net/eth.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/eth.c b/net/eth.c
> index 1e0821c5f8..b9bdd0435c 100644
> --- a/net/eth.c
> +++ b/net/eth.c
> @@ -405,6 +405,8 @@ _eth_get_rss_ex_dst_addr(const struct iovec *pkt, int
> pkt_frags,
> struct ip6_ext_hdr *ext_hdr,
> struct in6_address *dst_addr)
> {
> +#pragma GCC diagnostic push
> +#pragma GCC diagnostic ignored "-Warray-bounds"
> struct ip6_ext_hdr_routing *rthdr = (struct ip6_ext_hdr_routing *)
> ext_hdr;
eth_parse_ipv6_hdr() called iov_to_buf() to fill the 2 bytes of ext_hdr.
> if ((rthdr->rtype == 2) &&
Here we access after the 2 bytes filled... rthdr->rtype is somewhere on
eth_parse_ipv6_hdr's stack, its content is unknown.
> @@ -426,6 +428,7 @@ _eth_get_rss_ex_dst_addr(const struct iovec *pkt, int
> pkt_frags,
> }
>
> return false;
> +#pragma GCC diagnostic pop
Nacked-by: Philippe Mathieu-Daudé <phi...@redhat.com>
