Re: [PATCH v9 01/12] user_events: Add minimal support for trace_event into ftrace

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

Hi Beau,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on 85c62c8c3749eec02ba81217bdcac26867dc262e]

url:    https://github.com/0day-ci/linux/commits/Beau-Belgrave/user_events-Enable-user-processes-to-create-and-write-to-trace-events/20220112-014042
base:   85c62c8c3749eec02ba81217bdcac26867dc262e
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20220114/202201142322.DpkhCCS2-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 82c8aca93488730ce8f66101e0f3538f14b551dd)
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/0day-ci/linux/commit/a5a2d34cbaeb90d281d8c13c753f4aaaa447ec11
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Beau-Belgrave/user_events-Enable-user-processes-to-create-and-write-to-trace-events/20220112-014042
        git checkout a5a2d34cbaeb90d281d8c13c753f4aaaa447ec11
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash kernel/trace/ sound/soc/sof/

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_user.c:1027:14: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           return NULL + (*pos == 0);
                  ~~~~ ^
   1 warning generated.


vim +1027 kernel/trace/trace_events_user.c

  1024	
  1025	static void *user_seq_start(struct seq_file *m, loff_t *pos)
  1026	{
> 1027		return NULL + (*pos == 0);
  1028	}
  1029	

---
0-DAY CI Kernel Test Service, Intel Corporation
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