[kbuild-all] [oracle-dtrace:v1/5.15 30/35] net/ipv6/ip6_output.c:69:21: warning: variable 'dropreason' set but not used

tree: https://github.com/oracle/dtrace-linux-kernel v1/5.15 head: 0fee66d7ce96317146609675767971d0f35c3e74 commit: 7ed2333cfd691c676b0adfe951d92244f1ef5128 [30/35] dtrace: add SDT probes config: csky-defconfig (attached as .config) compiler: csky-linux-gcc (GCC) 11.2.0 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 # https://github.com/oracle/dtrace-linux-kernel/commit/7ed2333cfd691c676b0a... git remote add oracle-dtrace https://github.com/oracle/dtrace-linux-kernel git fetch --no-tags oracle-dtrace v1/5.15 git checkout 7ed2333cfd691c676b0adfe951d92244f1ef5128 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=csky If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): net/ipv6/ip6_output.c: In function 'ip6_finish_output2': 69 | const char *dropreason; | ^~~~~~~~~~ net/ipv6/ip6_output.c: In function 'ip6_xmit': net/ipv6/ip6_output.c:291:21: warning: variable 'dropreason' set but not used [-Wunused-but-set-variable] 291 | const char *dropreason; | ^~~~~~~~~~ net/ipv6/ip6_output.c: In function 'ip6_forward': 536 | int err = -EINVAL; | ^~~ net/ipv6/ip6_output.c:535:21: warning: variable 'dropreason' set but not used [-Wunused-but-set-variable] 535 | const char *dropreason; | ^~~~~~~~~~ net/ipv6/ip6_output.c: In function '__ip6_append_data': net/ipv6/ip6_output.c:1547:21: warning: variable 'dropreason' set but not used [-Wunused-but-set-variable] 1547 | const char *dropreason; | ^~~~~~~~~~ -- net/ipv6/ip6_input.c: In function 'ip6_rcv_core': 152 | const char *dropreason; | ^~~~~~~~~~ net/ipv6/ip6_input.c: In function 'ip6_protocol_deliver_rcu': net/ipv6/ip6_input.c:389:21: warning: variable 'dropreason' set but not used [-Wunused-but-set-variable] 389 | const char *dropreason; | ^~~~~~~~~~ net/ipv6/ip6_input.c: In function 'ip6_input': net/ipv6/ip6_input.c:526:25: warning: unused variable 'hdr' [-Wunused-variable] 526 | struct ipv6hdr *hdr = ipv6_hdr(skb); | ^~~ -- net/ipv6/raw.c: In function 'rawv6_send_hdrinc': 631 | const char *dropreason; | ^~~~~~~~~~ -- net/ipv6/mcast.c: In function 'mld_sendpack': 1796 | const char *dropreason; | ^~~~~~~~~~ net/ipv6/mcast.c: In function 'igmp6_send': net/ipv6/mcast.c:2167:21: warning: variable 'dropreason' set but not used [-Wunused-but-set-variable] 2167 | const char *dropreason; | ^~~~~~~~~~ vim +/dropreason +69 net/ipv6/ip6_output.c 59 60 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb) 61 { 62 struct dst_entry *dst = skb_dst(skb); 63 struct net_device *dev = dst->dev; 64 struct inet6_dev *idev = ip6_dst_idev(dst); 65 unsigned int hh_len = LL_RESERVED_SPACE(dev); 66 const struct in6_addr *daddr, *nexthop; 67 struct ipv6hdr *hdr; 68 struct neighbour *neigh; 70 int ret = 0; 71 72 /* Be paranoid, rather than too clever. */ 73 if (unlikely(hh_len > skb_headroom(skb)) && dev->header_ops) { 74 skb = skb_expand_head(skb, hh_len); 75 if (!skb) 76 goto oom; 77 } 78 79 hdr = ipv6_hdr(skb); 80 daddr = &hdr->daddr; 81 if (ipv6_addr_is_multicast(daddr)) { 82 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) && 83 ((mroute6_is_socket(net, skb) && 84 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) || 85 ipv6_chk_mcast_addr(dev, daddr, &hdr->saddr))) { 86 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); 87 88 /* Do not check for IFF_ALLMULTI; multicast routing 89 is not supported in any case. 90 */ 91 if (newskb) 92 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, 93 net, sk, newskb, NULL, newskb->dev, 94 dev_loopback_xmit); 95 96 if (hdr->hop_limit == 0) { 97 dropreason = "hoplimit exceeded"; 98 99 IP6_INC_STATS(net, idev, 100 IPSTATS_MIB_OUTDISCARDS); 101 goto drop; 102 } 103 } 104 105 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len); 106 if (IPV6_ADDR_MC_SCOPE(daddr) <= IPV6_ADDR_SCOPE_NODELOCAL && 107 !(dev->flags & IFF_LOOPBACK)) { 108 dropreason = "invalid scope"; 109 goto drop; 110 } 111 } 112 113 if (lwtunnel_xmit_redirect(dst->lwtstate)) { 114 int res = lwtunnel_xmit(skb); 115 116 if (res < 0 || res == LWTUNNEL_XMIT_DONE) 117 return res; 118 } 119 120 rcu_read_lock_bh(); 121 nexthop = rt6_nexthop((struct rt6_info *)dst, daddr); 122 neigh = __ipv6_neigh_lookup_noref(dev, nexthop); 123 if (unlikely(!neigh)) 124 neigh = __neigh_create(&nd_tbl, nexthop, dev, false); 125 if (!IS_ERR(neigh)) { 126 sock_confirm_neigh(skb, neigh); 127 ret = neigh_output(neigh, skb, false); 128 rcu_read_unlock_bh(); 129 return ret; 130 } 131 rcu_read_unlock_bh(); 132 133 dropreason = "no route to host"; 134 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTNOROUTES); 135 ret = -EINVAL; 136 drop: 137 DTRACE_IP(drop__out, 138 struct sk_buff * : pktinfo_t *, skb, 139 struct sock * : csinfo_t *, skb->sk, 140 void_ip_t * : ipinfo_t *, ipv6_hdr(skb), 141 struct net_device * : ifinfo_t *, skb->dev, 142 struct iphdr * : ipv4info_t *, NULL, 143 struct ipv6hdr * : ipv6info_t *, ipv6_hdr(skb), 144 const char * : string, dropreason); 145 kfree_skb(skb); 146 return ret; 147 oom: 148 DTRACE_IP(drop__out, 149 struct sk_buff * : pktinfo_t *, NULL, 150 struct sock * : csinfo_t *, NULL, 151 void_ip_t * : ipinfo_t *, NULL, 152 struct net_device * : ifinfo_t *, NULL, 153 struct iphdr * : ipv4info_t *, NULL, 154 struct ipv6hdr * : ipv6info_t *, NULL, 155 const char * : string, "out of memory"); 156 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); 157 return -ENOMEM; 158 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org