From 810c23a3553cbb4602edf9534b548d2616ba5520 Mon Sep 17 00:00:00 2001 From: Jerry Chu Date: Sun, 15 Dec 2013 18:48:07 -0800 Subject: [PATCH] net-ipv6: Fix alleged compiler warning in ipv6_exthdrs_len() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit It was reported that Commit 299603e8370a93dd5d8e8d800f0dff1ce2c53d36 ("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 Signed-off-by: H.K. Jerry Chu Signed-off-by: David S. Miller --- net/ipv6/ip6_offload.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index 08861f1ff883..6fb4162fa785 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -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; - } + opth = (void *)opth + optlen; + optlen = ipv6_optlen(opth); len += optlen; proto = opth->nexthdr; } -- 2.20.1