Re: [PATCH net-next] icmp: Add icmp_timestamp_ignore_all to control ICMP_TIMESTAMP

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

Hi,

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/ye-xingchen-zte-com-cn/icmp-Add-icmp_timestamp_ignore_all-to-control-ICMP_TIMESTAMP/20240517-172903
base:   net-next/main
patch link:    https://lore.kernel.org/r/20240517172639229ec5bN7VBV7SGEHkSK5K6f%40zte.com.cn
patch subject: [PATCH net-next] icmp: Add icmp_timestamp_ignore_all to control ICMP_TIMESTAMP
config: arc-vdk_hs38_defconfig (https://download.01.org/0day-ci/archive/20240518/202405180527.iGJVxmda-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240518/202405180527.iGJVxmda-lkp@intel.com/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 <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405180527.iGJVxmda-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from ./arch/arc/include/generated/asm/rwonce.h:1,
                    from include/linux/compiler.h:299,
                    from include/linux/build_bug.h:5,
                    from include/linux/container_of.h:5,
                    from include/linux/list.h:5,
                    from include/linux/module.h:12,
                    from net/ipv4/icmp.c:62:
   net/ipv4/icmp.c: In function 'icmp_timestamp':
>> include/asm-generic/rwonce.h:44:71: warning: 'net' is used uninitialized [-Wuninitialized]
      44 | #define __READ_ONCE(x)  (*(const volatile __unqual_scalar_typeof(x) *)&(x))
         |                                                                       ^~~~
   include/asm-generic/rwonce.h:50:9: note: in expansion of macro '__READ_ONCE'
      50 |         __READ_ONCE(x);                                                 \
         |         ^~~~~~~~~~~
   net/ipv4/icmp.c:1157:13: note: in expansion of macro 'READ_ONCE'
    1157 |         if (READ_ONCE(net->ipv4.sysctl_icmp_timestamp_ignore_all))
         |             ^~~~~~~~~
   net/ipv4/icmp.c:1155:21: note: 'net' was declared here
    1155 |         struct net *net;
         |                     ^~~


vim +/net +44 include/asm-generic/rwonce.h

e506ea451254ab1 Will Deacon 2019-10-15  28  
e506ea451254ab1 Will Deacon 2019-10-15  29  /*
e506ea451254ab1 Will Deacon 2019-10-15  30   * Yes, this permits 64-bit accesses on 32-bit architectures. These will
e506ea451254ab1 Will Deacon 2019-10-15  31   * actually be atomic in some cases (namely Armv7 + LPAE), but for others we
e506ea451254ab1 Will Deacon 2019-10-15  32   * rely on the access being split into 2x32-bit accesses for a 32-bit quantity
e506ea451254ab1 Will Deacon 2019-10-15  33   * (e.g. a virtual address) and a strong prevailing wind.
e506ea451254ab1 Will Deacon 2019-10-15  34   */
e506ea451254ab1 Will Deacon 2019-10-15  35  #define compiletime_assert_rwonce_type(t)					\
e506ea451254ab1 Will Deacon 2019-10-15  36  	compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long),	\
e506ea451254ab1 Will Deacon 2019-10-15  37  		"Unsupported access size for {READ,WRITE}_ONCE().")
e506ea451254ab1 Will Deacon 2019-10-15  38  
e506ea451254ab1 Will Deacon 2019-10-15  39  /*
e506ea451254ab1 Will Deacon 2019-10-15  40   * Use __READ_ONCE() instead of READ_ONCE() if you do not require any
3c9184109e78ea2 Will Deacon 2019-10-30  41   * atomicity. Note that this may result in tears!
e506ea451254ab1 Will Deacon 2019-10-15  42   */
b78b331a3f5c077 Will Deacon 2019-10-15  43  #ifndef __READ_ONCE
e506ea451254ab1 Will Deacon 2019-10-15 @44  #define __READ_ONCE(x)	(*(const volatile __unqual_scalar_typeof(x) *)&(x))
b78b331a3f5c077 Will Deacon 2019-10-15  45  #endif
e506ea451254ab1 Will Deacon 2019-10-15  46  

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