Subject: Re: [PATCH net-next 2/2] tcp: add more warn of socket in tcp_send_loss_probe()

From: kernel test robot <[email-masked]>
Date: Mon, 21 Oct 2024 13:52:06 +0800

Hi Jason,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Jason-Xing/tcp-add-a-common-helper-to-debug-the-underlying-issue/20241020-225356
base:   net-next/main
patch link:    https://lore.kernel.org/r/20241020145029.27725-3-kerneljasonxing%40gmail.com
patch subject: [PATCH net-next 2/2] tcp: add more warn of socket in tcp_send_loss_probe()
config: x86_64-rhel-8.3 (https://download.01.org/0day-ci/archive/20241021/[email-masked]/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241021/[email-masked]/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email-masked]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email-masked]/

All warnings (new ones prefixed by >>):

   In file included from arch/x86/include/asm/bug.h:99,
                    from include/linux/bug.h:5,
                    from include/linux/fortify-string.h:6,
                    from include/linux/string.h:390,
                    from include/linux/bitmap.h:13,
                    from include/linux/cpumask.h:12,
                    from arch/x86/include/asm/cpumask.h:5,
                    from arch/x86/include/asm/msr.h:11,
                    from arch/x86/include/asm/tsc.h:10,
                    from arch/x86/include/asm/timex.h:6,
                    from include/linux/timex.h:67,
                    from include/linux/time32.h:13,
                    from include/linux/time.h:60,
                    from include/linux/skbuff.h:15,
                    from include/linux/tcp.h:17,
                    from include/net/tcp.h:20,
                    from net/ipv4/tcp_output.c:40:
   In function 'tcp_warn_once',
       inlined from 'tcp_warn_once' at include/net/tcp.h:2433:20,
       inlined from 'tcp_send_loss_probe' at net/ipv4/tcp_output.c:2957:3:
>> include/net/tcp.h:2436:19: warning: '%s' directive argument is null [-Wformat-overflow=]
    2436 |                   "%s"
         |                   ^~~~
   include/asm-generic/bug.h:106:31: note: in definition of macro '__WARN_printf'
     106 |                 __warn_printk(arg);                                     \
         |                               ^~~
   include/linux/once_lite.h:31:25: note: in expansion of macro 'WARN'
      31 |                         func(__VA_ARGS__);                              \
         |                         ^~~~
   include/asm-generic/bug.h:152:9: note: in expansion of macro 'DO_ONCE_LITE_IF'
     152 |         DO_ONCE_LITE_IF(condition, WARN, 1, format)
         |         ^~~~~~~~~~~~~~~
   include/net/tcp.h:2435:9: note: in expansion of macro 'WARN_ONCE'
    2435 |         WARN_ONCE(cond,
         |         ^~~~~~~~~
   include/net/tcp.h: In function 'tcp_send_loss_probe':
   include/net/tcp.h:2436:20: note: format string is defined here
    2436 |                   "%s"
         |                    ^~

vim +2436 include/net/tcp.h

1a91bb7c3ebf95 Mubashir Adnan Qureshi 2022-10-26  2432  
4fe1493c15028c Jason Xing             2024-10-20  2433  static inline void tcp_warn_once(const struct sock *sk, bool cond, const char *str)
4fe1493c15028c Jason Xing             2024-10-20  2434  {
4fe1493c15028c Jason Xing             2024-10-20  2435  	WARN_ONCE(cond,
4fe1493c15028c Jason Xing             2024-10-20 @2436  		  "%s"
d21098f05ea727 Jason Xing             2024-10-20  2437  		  "cwnd:%u "
4fe1493c15028c Jason Xing             2024-10-20  2438  		  "out:%u sacked:%u lost:%u retrans:%u "
4fe1493c15028c Jason Xing             2024-10-20  2439  		  "tlp_high_seq:%u sk_state:%u ca_state:%u "
d21098f05ea727 Jason Xing             2024-10-20  2440  		  "mss:%u advmss:%u mss_cache:%u pmtu:%u\n",
4fe1493c15028c Jason Xing             2024-10-20  2441  		  str,
d21098f05ea727 Jason Xing             2024-10-20  2442  		  tcp_snd_cwnd(tcp_sk(sk)),
4fe1493c15028c Jason Xing             2024-10-20  2443  		  tcp_sk(sk)->packets_out, tcp_sk(sk)->sacked_out,
4fe1493c15028c Jason Xing             2024-10-20  2444  		  tcp_sk(sk)->lost_out, tcp_sk(sk)->retrans_out,
4fe1493c15028c Jason Xing             2024-10-20  2445  		  tcp_sk(sk)->tlp_high_seq, sk->sk_state,
4fe1493c15028c Jason Xing             2024-10-20  2446  		  inet_csk(sk)->icsk_ca_state,
d21098f05ea727 Jason Xing             2024-10-20  2447  		  tcp_current_mss((struct sock *)sk),
4fe1493c15028c Jason Xing             2024-10-20  2448  		  tcp_sk(sk)->advmss, tcp_sk(sk)->mss_cache,
4fe1493c15028c Jason Xing             2024-10-20  2449  		  inet_csk(sk)->icsk_pmtu_cookie);
4fe1493c15028c Jason Xing             2024-10-20  2450  }
4fe1493c15028c Jason Xing             2024-10-20  2451  

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