Re: [PATCH] tcp: Fix tcp_max_syn_backlog limit on connection requests

[kbuild test robot <lkp@intel.com>]

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Hi Ttttabcd,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net/master]
[also build test WARNING on net-next/master ipvs/master v5.5-rc4 next-20191220]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Ttttabcd/tcp-Fix-tcp_max_syn_backlog-limit-on-connection-requests/20191230-164004
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git bb3d0b8bf5be61ab1d6f472c43cbf34de17e796b
config: um-x86_64_defconfig (attached as .config)
compiler: gcc-7 (Debian 7.5.0-3) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=um SUBARCH=x86_64

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/asm-generic/bug.h:19:0,
                    from ./arch/um/include/generated/asm/bug.h:1,
                    from include/linux/bug.h:5,
                    from include/linux/mmdebug.h:5,
                    from include/linux/mm.h:9,
                    from net/ipv4/tcp_input.c:67:
   net/ipv4/tcp_input.c: In function 'tcp_conn_request':
   include/linux/kernel.h:844:29: warning: comparison of distinct pointer types lacks a cast
      (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                                ^
   include/linux/kernel.h:858:4: note: in expansion of macro '__typecheck'
      (__typecheck(x, y) && __no_side_effects(x, y))
       ^~~~~~~~~~~
   include/linux/kernel.h:868:24: note: in expansion of macro '__safe_cmp'
     __builtin_choose_expr(__safe_cmp(x, y), \
                           ^~~~~~~~~~
   include/linux/kernel.h:877:19: note: in expansion of macro '__careful_cmp'
    #define min(x, y) __careful_cmp(x, y, <)
                      ^~~~~~~~~~~~~
>> net/ipv4/tcp_input.c:6568:20: note: in expansion of macro 'min'
     max_syn_backlog = min(net->ipv4.sysctl_max_syn_backlog,
                       ^~~

vim +/min +6568 net/ipv4/tcp_input.c

  6551	
  6552	int tcp_conn_request(struct request_sock_ops *rsk_ops,
  6553			     const struct tcp_request_sock_ops *af_ops,
  6554			     struct sock *sk, struct sk_buff *skb)
  6555	{
  6556		struct tcp_fastopen_cookie foc = { .len = -1 };
  6557		__u32 isn = TCP_SKB_CB(skb)->tcp_tw_isn;
  6558		struct tcp_options_received tmp_opt;
  6559		struct tcp_sock *tp = tcp_sk(sk);
  6560		struct net *net = sock_net(sk);
  6561		struct sock *fastopen_sk = NULL;
  6562		struct request_sock *req;
  6563		bool want_cookie = false;
  6564		struct dst_entry *dst;
  6565		int max_syn_backlog;
  6566		struct flowi fl;
  6567	
> 6568		max_syn_backlog = min(net->ipv4.sysctl_max_syn_backlog,

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation

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