Commit 810c23a3 authored Dec 15, 2013 by Jerry Chu Committed by David S. Miller Dec 15, 2013

net-ipv6: Fix alleged compiler warning in ipv6_exthdrs_len()



It was reported that Commit 299603e8
("net-gro: Prepare GRO stack for the upcoming tunneling support")
triggered a compiler warning in ipv6_exthdrs_len():

net/ipv6/ip6_offload.c: In function ‘ipv6_gro_complete’:
net/ipv6/ip6_offload.c:178:24: warning: ‘optlen’ may be used uninitialized in this function [-Wmaybe-u
    opth = (void *)opth + optlen;
    			^
    net/ipv6/ip6_offload.c:164:22: note: ‘optlen’ was declared here
    int len = 0, proto, optlen;
                        ^
Note that there was no real bug here - optlen was never uninitialized
before use. (Was the version of gcc I used smarter to not complain?)

Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: H.K. Jerry Chu <hkchu@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 7ed2a0d0

net/ipv6/ip6_offload.c

+4 −8

Original line number	Diff line number	Diff line
		@@ -160,8 +160,8 @@ out:
		static int ipv6_exthdrs_len(struct ipv6hdr *iph,
		const struct net_offload **opps)
		{
		struct ipv6_opt_hdr *opth = NULL;
		int len = 0, optlen = 0, proto;
		struct ipv6_opt_hdr opth = (void )iph;
		int len = 0, proto, optlen = sizeof(*iph);

		proto = iph->nexthdr;
		for (;;) {
		@@ -172,12 +172,8 @@ static int ipv6_exthdrs_len(struct ipv6hdr *iph,
		if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
		break;
		}
		if (opth == NULL) {
		opth = (void *)(iph+1);
		} else {
		optlen = ipv6_optlen(opth);
		opth = (void *)opth + optlen;
		}
		optlen = ipv6_optlen(opth);
		len += optlen;
		proto = opth->nexthdr;
		}

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