[ammarfaizi2-block:rostedt/linux-trace/for-next 19/32] kernel/trace/trace_events_synth.c:65:9: warning: 'strncpy' specified bound depends on the length of the source argument

[ammarfaizi2-block:rostedt/linux-trace/for-next 19/32] kernel/trace/trace_events_synth.c:65:9: warning: 'strncpy' specified bound depends on the length of the source argument

[kernel test robot]

tree:   https://github.com/ammarfaizi2/linux-block rostedt/linux-trace/for-next
head:   864ea0e10cc90416a01b46f0d47a6f26dc020820
commit: 27c888da9867725784bad3d6455d6e53b425fa2b [19/32] tracing: Remove size restriction on synthetic event cmd error logging
config: arm-randconfig-r022-20220221 (https://download.01.org/0day-ci/archive/20220222/202202220258.LyXgZyyT-lkp@intel.com/config)
compiler: arm-linux-gnueabi-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/ammarfaizi2/linux-block/commit/27c888da9867725784bad3d6455d6e53b425fa2b
        git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
        git fetch --no-tags ammarfaizi2-block rostedt/linux-trace/for-next
        git checkout 27c888da9867725784bad3d6455d6e53b425fa2b
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm SHELL=/bin/bash kernel/trace/

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

All warnings (new ones prefixed by >>):

   kernel/trace/trace_events_synth.c: In function 'last_cmd_set':
>> kernel/trace/trace_events_synth.c:65:9: warning: 'strncpy' specified bound depends on the length of the source argument [-Wstringop-truncation]
      65 |         strncpy(last_cmd, str, strlen(str) + 1);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_events_synth.c:65:32: note: length computed here
      65 |         strncpy(last_cmd, str, strlen(str) + 1);
         |                                ^~~~~~~~~~~


vim +/strncpy +65 kernel/trace/trace_events_synth.c

    54	
    55	static void last_cmd_set(const char *str)
    56	{
    57		if (!str)
    58			return;
    59	
    60		kfree(last_cmd);
    61		last_cmd = kzalloc(strlen(str) + 1, GFP_KERNEL);
    62		if (!last_cmd)
    63			return;
    64	
  > 65		strncpy(last_cmd, str, strlen(str) + 1);
    66	}
    67	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org