Hi Gao,

[auto build test WARNING on nf/master]

url:    https://github.com/0day-ci/linux/commits/gfree-wind-foxmail-com/netfilter-snmp-Fix-one-possible-panic-when-snmp_trap_helper-fail-to-register/20170327-081220
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf.git master
config: x86_64-randconfig-s2-03272042 (attached as .config)
compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   net/ipv4//netfilter/nf_nat_snmp_basic.c: In function 'nf_nat_snmp_basic_init':
>> net/ipv4//netfilter/nf_nat_snmp_basic.c:1281: warning: unused variable 'ret'

vim +/ret +1281 net/ipv4//netfilter/nf_nat_snmp_basic.c

807467c22 Patrick McHardy   2006-12-02  1265  	.help			= help,
6002f266b Patrick McHardy   2008-03-25  1266  	.expect_policy		= &snmp_exp_policy,
807467c22 Patrick McHardy   2006-12-02  1267  	.name			= "snmp_trap",
807467c22 Patrick McHardy   2006-12-02  1268  	.tuple.src.l3num	= AF_INET,
09640e636 Harvey Harrison   2009-02-01  1269  	.tuple.src.u.udp.port	= cpu_to_be16(SNMP_TRAP_PORT),
807467c22 Patrick McHardy   2006-12-02  1270  	.tuple.dst.protonum	= IPPROTO_UDP,
807467c22 Patrick McHardy   2006-12-02  1271  };
807467c22 Patrick McHardy   2006-12-02  1272  
807467c22 Patrick McHardy   2006-12-02  1273  /*****************************************************************************
807467c22 Patrick McHardy   2006-12-02  1274   *
807467c22 Patrick McHardy   2006-12-02  1275   * Module stuff.
807467c22 Patrick McHardy   2006-12-02  1276   *
807467c22 Patrick McHardy   2006-12-02  1277   *****************************************************************************/
807467c22 Patrick McHardy   2006-12-02  1278  
807467c22 Patrick McHardy   2006-12-02  1279  static int __init nf_nat_snmp_basic_init(void)
807467c22 Patrick McHardy   2006-12-02  1280  {
807467c22 Patrick McHardy   2006-12-02 @1281  	int ret = 0;
807467c22 Patrick McHardy   2006-12-02  1282  
93557f53e Jiri Olsa         2011-01-18  1283  	BUG_ON(nf_nat_snmp_hook != NULL);
a9b3cd7f3 Stephen Hemminger 2011-08-01  1284  	RCU_INIT_POINTER(nf_nat_snmp_hook, help);
93557f53e Jiri Olsa         2011-01-18  1285  
9b25a2987 Gao Feng          2017-03-25  1286  	return nf_conntrack_helper_register(&snmp_trap_helper);
807467c22 Patrick McHardy   2006-12-02  1287  }
807467c22 Patrick McHardy   2006-12-02  1288  
807467c22 Patrick McHardy   2006-12-02  1289  static void __exit nf_nat_snmp_basic_fini(void)

:::::: The code at line 1281 was first introduced by commit
:::::: 807467c22a12381985878be23c778657fc0364d0 [NETFILTER]: nf_nat: add SNMP NAT helper port

:::::: TO: Patrick McHardy <kaber@trash.net>
:::::: CC: David S. Miller <davem@davemloft.net>

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