Hi Cong, [auto build test WARNING on net/master] url: https://github.com/0day-ci/linux/commits/Cong-Wang/ipv6-check-for-ip6_null_entry-in-__ip6_del_rt_siblings/20170228-135206 config: x86_64-randconfig-x017-201709 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): Cyclomatic Complexity 3 include/net/sock.h:lockdep_sock_is_held Cyclomatic Complexity 5 include/net/sock.h:__sk_dst_get Cyclomatic Complexity 6 include/net/sock.h:sock_owned_by_me Cyclomatic Complexity 1 include/net/sock.h:sock_owned_by_user Cyclomatic Complexity 5 include/net/addrconf.h:__in6_dev_get Cyclomatic Complexity 11 net/ipv6/route.c:rt6_mtu_change_route Cyclomatic Complexity 4 net/ipv6/route.c:ip6_mtu Cyclomatic Complexity 3 include/net/neighbour.h:__neigh_lookup Cyclomatic Complexity 2 include/net/neighbour.h:neigh_release Cyclomatic Complexity 2 net/ipv6/route.c:ip6_print_replace_route_err Cyclomatic Complexity 6 net/ipv6/route.c:ip6_pkt_drop Cyclomatic Complexity 1 net/ipv6/route.c:ip6_pkt_discard Cyclomatic Complexity 1 net/ipv6/route.c:ip6_pkt_discard_out Cyclomatic Complexity 1 net/ipv6/route.c:ip6_pkt_prohibit Cyclomatic Complexity 1 net/ipv6/route.c:ip6_pkt_prohibit_out Cyclomatic Complexity 12 net/ipv6/route.c:ip6_convert_metrics Cyclomatic Complexity 7 net/ipv6/route.c:ip6_route_info_append Cyclomatic Complexity 3 net/ipv6/route.c:__ip6_del_rt Cyclomatic Complexity 2 arch/x86/include/asm/uaccess.h:copy_user_overflow Cyclomatic Complexity 2 net/ipv6/route.c:rt6_nlmsg_size Cyclomatic Complexity 1 include/linux/skbuff.h:alloc_skb Cyclomatic Complexity 1 include/net/netlink.h:nlmsg_new Cyclomatic Complexity 2 include/net/netlink.h:nlmsg_put Cyclomatic Complexity 5 include/net/ip6_route.h:ip6_route_get_saddr Cyclomatic Complexity 1 include/net/netlink.h:nla_put_in6_addr Cyclomatic Complexity 1 include/net/netlink.h:nla_put_u32 Cyclomatic Complexity 2 include/net/netlink.h:nla_nest_start Cyclomatic Complexity 1 include/net/netlink.h:nla_put_u8 Cyclomatic Complexity 10 net/ipv6/route.c:rt6_nexthop_info Cyclomatic Complexity 4 net/ipv6/route.c:rt6_add_nexthop Cyclomatic Complexity 3 include/net/netlink.h:nlmsg_trim Cyclomatic Complexity 1 include/net/netlink.h:nlmsg_cancel Cyclomatic Complexity 38 net/ipv6/route.c:rt6_fill_node Cyclomatic Complexity 10 net/ipv6/route.c:__ip6_del_rt_siblings Cyclomatic Complexity 16 net/ipv6/route.c:ip6_route_del Cyclomatic Complexity 6 net/ipv6/route.c:ip6_dst_gc Cyclomatic Complexity 2 net/ipv6/route.c:ipv6_sysctl_rtcache_flush Cyclomatic Complexity 5 net/ipv6/route.c:ip6_route_net_init Cyclomatic Complexity 2 include/net/netlink.h:nlmsg_parse Cyclomatic Complexity 1 include/net/netlink.h:nla_get_in6_addr Cyclomatic Complexity 24 net/ipv6/route.c:rtm_to_fib6_config Cyclomatic Complexity 6 net/ipv6/route.c:ip6_route_multipath_del Cyclomatic Complexity 3 net/ipv6/route.c:inet6_rtm_delroute Cyclomatic Complexity 1 net/ipv6/route.c:ip6_route_net_exit_late Cyclomatic Complexity 1 net/ipv6/route.c:rt6_stats_seq_open Cyclomatic Complexity 1 net/ipv6/route.c:rt6_stats_seq_show Cyclomatic Complexity 1 include/linux/proc_fs.h:proc_create Cyclomatic Complexity 1 net/ipv6/route.c:ip6_route_net_init_late Cyclomatic Complexity 1 net/ipv6/route.c:ipv6_inetpeer_exit Cyclomatic Complexity 2 net/ipv6/route.c:ipv6_inetpeer_init Cyclomatic Complexity 4 net/ipv6/route.c:ip6_dst_alloc Cyclomatic Complexity 1 net/ipv6/route.c:ip6_route_lookup Cyclomatic Complexity 3 net/ipv6/route.c:rt6_lookup Cyclomatic Complexity 1 net/ipv6/route.c:ip6_ins_rt Cyclomatic Complexity 9 net/ipv6/route.c:__ip6_rt_update_pmtu Cyclomatic Complexity 2 net/ipv6/route.c:ip6_rt_update_pmtu Cyclomatic Complexity 13 net/ipv6/route.c:ip6_pol_route Cyclomatic Complexity 1 net/ipv6/route.c:ip6_pol_route_input Cyclomatic Complexity 1 net/ipv6/route.c:ip6_pol_route_output Cyclomatic Complexity 4 net/ipv6/route.c:ip6_nh_lookup_table Cyclomatic Complexity 59 net/ipv6/route.c:ip6_route_info_create Cyclomatic Complexity 3 net/ipv6/route.c:ip6_route_input_lookup Cyclomatic Complexity 3 net/ipv6/route.c:ip6_route_input Cyclomatic Complexity 10 net/ipv6/route.c:ip6_route_output_flags Cyclomatic Complexity 1 include/net/ip6_route.h:ip6_route_output Cyclomatic Complexity 18 net/ipv6/route.c:inet6_rtm_getroute Cyclomatic Complexity 4 net/ipv6/route.c:ip6_blackhole_route Cyclomatic Complexity 4 net/ipv6/route.c:ip6_update_pmtu Cyclomatic Complexity 6 net/ipv6/route.c:ip6_sk_update_pmtu Cyclomatic Complexity 3 net/ipv6/route.c:icmp6_dst_alloc Cyclomatic Complexity 3 net/ipv6/route.c:icmp6_dst_gc Cyclomatic Complexity 4 net/ipv6/route.c:ip6_route_add Cyclomatic Complexity 3 net/ipv6/route.c:rt6_add_route_info Cyclomatic Complexity 1 net/ipv6/route.c:ip6_del_rt Cyclomatic Complexity 30 net/ipv6/route.c:rt6_do_redirect Cyclomatic Complexity 1 net/ipv6/route.c:ip6_redirect Cyclomatic Complexity 1 net/ipv6/route.c:ip6_sk_redirect Cyclomatic Complexity 1 net/ipv6/route.c:ip6_redirect_no_header Cyclomatic Complexity 5 net/ipv6/route.c:__rt6_purge_dflt_routers Cyclomatic Complexity 5 net/ipv6/route.c:ip6_link_failure Cyclomatic Complexity 4 net/ipv6/route.c:ip6_negative_advice Cyclomatic Complexity 8 net/ipv6/route.c:rt6_get_dflt_router Cyclomatic Complexity 16 net/ipv6/route.c:rt6_route_rcv Cyclomatic Complexity 4 net/ipv6/route.c:rt6_add_dflt_router Cyclomatic Complexity 6 net/ipv6/route.c:rt6_purge_dflt_routers Cyclomatic Complexity 6 net/ipv6/route.c:ipv6_route_ioctl Cyclomatic Complexity 6 net/ipv6/route.c:addrconf_dst_alloc Cyclomatic Complexity 1 net/ipv6/route.c:rt6_remove_prefsrc Cyclomatic Complexity 1 net/ipv6/route.c:rt6_clean_tohost Cyclomatic Complexity 2 net/ipv6/route.c:rt6_ifdown Cyclomatic Complexity 1 net/ipv6/route.c:rt6_mtu_change Cyclomatic Complexity 5 net/ipv6/route.c:rt6_dump_route Cyclomatic Complexity 6 net/ipv6/route.c:inet6_rt_notify Cyclomatic Complexity 5 net/ipv6/route.c:ip6_route_mpath_notify Cyclomatic Complexity 22 net/ipv6/route.c:ip6_route_multipath_add Cyclomatic Complexity 3 net/ipv6/route.c:inet6_rtm_newroute Cyclomatic Complexity 3 net/ipv6/route.c:ipv6_route_sysctl_init Cyclomatic Complexity 14 net/ipv6/route.c:ip6_route_init Cyclomatic Complexity 1 net/ipv6/route.c:ip6_route_cleanup net/ipv6/route.c: In function 'ip6_route_del': >> net/ipv6/route.c:2175:6: warning: 'err' may be used uninitialized in this function [-Wmaybe-uninitialized] int err; ^~~ vim +/err +2175 net/ipv6/route.c ^1da177e4 Linus Torvalds 2005-04-16 2159 } ^1da177e4 Linus Torvalds 2005-04-16 2160 e0a1ad73d Thomas Graf 2006-08-22 2161 int ip6_del_rt(struct rt6_info *rt) e0a1ad73d Thomas Graf 2006-08-22 2162 { 4d1169c1e Denis V. Lunev 2008-01-10 2163 struct nl_info info = { d19185428 David S. Miller 2011-12-28 2164 .nl_net = dev_net(rt->dst.dev), 4d1169c1e Denis V. Lunev 2008-01-10 2165 }; 528c4ceb4 Denis V. Lunev 2007-12-13 2166 return __ip6_del_rt(rt, &info); e0a1ad73d Thomas Graf 2006-08-22 2167 } e0a1ad73d Thomas Graf 2006-08-22 2168 0ae813358 David Ahern 2017-02-02 2169 static int __ip6_del_rt_siblings(struct rt6_info *rt, struct fib6_config *cfg) 0ae813358 David Ahern 2017-02-02 2170 { 0ae813358 David Ahern 2017-02-02 2171 struct nl_info *info = &cfg->fc_nlinfo; f0c30f4c1 Cong Wang 2017-02-27 2172 struct net *net = info->nl_net; 16a16cd35 David Ahern 2017-02-02 2173 struct sk_buff *skb = NULL; 0ae813358 David Ahern 2017-02-02 2174 struct fib6_table *table; 0ae813358 David Ahern 2017-02-02 @2175 int err; 0ae813358 David Ahern 2017-02-02 2176 f0c30f4c1 Cong Wang 2017-02-27 2177 if (rt == net->ipv6.ip6_null_entry) f0c30f4c1 Cong Wang 2017-02-27 2178 goto out_put; 0ae813358 David Ahern 2017-02-02 2179 table = rt->rt6i_table; 0ae813358 David Ahern 2017-02-02 2180 write_lock_bh(&table->tb6_lock); 0ae813358 David Ahern 2017-02-02 2181 0ae813358 David Ahern 2017-02-02 2182 if (rt->rt6i_nsiblings && cfg->fc_delete_all_nh) { 0ae813358 David Ahern 2017-02-02 2183 struct rt6_info *sibling, *next_sibling; :::::: The code at line 2175 was first introduced by commit :::::: 0ae8133586ad1c9be894411aaf8b17bb58c8efe5 net: ipv6: Allow shorthand delete of all nexthops in multipath route :::::: TO: David Ahern :::::: CC: David S. 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