tree: https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git pending-4.19 head: da0ab6f9b4814a4a16e1999273d7dbd1a348314b commit: 56335d9a0cf022794203699503e5fd63176210b4 [46/61] net: use indirect calls helpers at early demux stage config: x86_64-randconfig-a002-20210620 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project d1baf2895467735ab14f4b3415fce204c0cc8e7f) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git/c... git remote add sashal-linux-stable https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git git fetch --no-tags sashal-linux-stable pending-4.19 git checkout 56335d9a0cf022794203699503e5fd63176210b4 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>): INDIRECT_CALLABLE_DECLARE(int udp_v4_early_demux(struct sk_buff *)); ^ int net/ipv4/ip_input.c:310:1: warning: declaration specifier missing, defaulting to 'int' INDIRECT_CALLABLE_DECLARE(int tcp_v4_early_demux(struct sk_buff *)); ^ int err = INDIRECT_CALL_2(edemux, tcp_v4_early_demux, ^ err = INDIRECT_CALL_2(edemux, tcp_v4_early_demux, ^ udp_v4_early_demux, skb); ^ 2 warnings and 3 errors generated. -- INDIRECT_CALLABLE_DECLARE(void udp_v6_early_demux(struct sk_buff *)); ^ int net/ipv6/ip6_input.c:51:1: warning: declaration specifier missing, defaulting to 'int' INDIRECT_CALLABLE_DECLARE(void tcp_v6_early_demux(struct sk_buff *)); ^ int INDIRECT_CALL_2(edemux, tcp_v6_early_demux, ^ INDIRECT_CALL_2(edemux, tcp_v6_early_demux, ^ udp_v6_early_demux, skb); ^ 2 warnings and 3 errors generated. -- INDIRECT_CALLABLE_SCOPE void udp_v6_early_demux(struct sk_buff *skb) ^ return; ^ net/ipv6/udp.c:936:3: error: non-void function 'udp_v6_early_demux' should return a value [-Wreturn-type] return; ^ net/ipv6/udp.c:939:3: error: non-void function 'udp_v6_early_demux' should return a value [-Wreturn-type] return; ^ 4 errors generated. -- INDIRECT_CALLABLE_SCOPE void tcp_v6_early_demux(struct sk_buff *skb) ^ return; ^ net/ipv6/tcp_ipv6.c:1656:3: error: non-void function 'tcp_v6_early_demux' should return a value [-Wreturn-type] return; ^ net/ipv6/tcp_ipv6.c:1662:3: error: non-void function 'tcp_v6_early_demux' should return a value [-Wreturn-type] return; ^ 4 errors generated. vim +/INDIRECT_CALL_2 +328 net/ipv4/ip_input.c 308 310 INDIRECT_CALLABLE_DECLARE(int tcp_v4_early_demux(struct sk_buff *)); 311 static int ip_rcv_finish_core(struct net *net, struct sock *sk, 312 struct sk_buff *skb, struct net_device *dev) 313 { 314 const struct iphdr *iph = ip_hdr(skb); 315 int (*edemux)(struct sk_buff *skb); 316 struct rtable *rt; 317 int err; 318 319 if (net->ipv4.sysctl_ip_early_demux && 320 !skb_dst(skb) && 321 !skb->sk && 322 !ip_is_fragment(iph)) { 323 const struct net_protocol *ipprot; 324 int protocol = iph->protocol; 325 326 ipprot = rcu_dereference(inet_protos[protocol]); 327 if (ipprot && (edemux = READ_ONCE(ipprot->early_demux))) { 330 if (unlikely(err)) 331 goto drop_error; 332 /* must reload iph, skb->head might have changed */ 333 iph = ip_hdr(skb); 334 } 335 } 336 337 /* 338 * Initialise the virtual path cache for the packet. It describes 339 * how the packet travels inside Linux networking. 340 */ 341 if (!skb_valid_dst(skb)) { 342 err = ip_route_input_noref(skb, iph->daddr, iph->saddr, 343 iph->tos, dev); 344 if (unlikely(err)) 345 goto drop_error; 346 } 347 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org