netfilter: avoid erronous array bounds warning
Unfortunately some versions of gcc emit following warning:
$ make net/xfrm/xfrm_output.o
linux/compiler.h:252:20: warning: array subscript is above array bounds [-Warray-bounds]
hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
^~~~~~~~~~~~~~~~~~~~~
xfrm_output_resume passes skb_dst(skb)->ops->family as its 'pf' arg so compiler
can't know that we'll never access hooks_arp[].
(NFPROTO_IPV4 or NFPROTO_IPV6 are only possible cases).
Avoid this by adding an explicit WARN_ON_ONCE() check.
This patch has no effect if the family is a compile-time constant as gcc
will remove the switch() construct entirely.
Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
1 file changed