Re: [RFC][PATCH v6 1/5] trace: Add trace any kernel object

Re: [RFC][PATCH v6 1/5] trace: Add trace any kernel object

[kernel test robot]

Hi Jeff,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on rostedt-trace/for-next]
[also build test WARNING on linux/master linus/master v5.16-rc3 next-20211129]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Jeff-Xie/trace-Introduce-objtrace-trigger-to-trace-the-kernel-object/20211130-041958
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next
config: i386-buildonly-randconfig-r003-20211128 (https://download.01.org/0day-ci/archive/20211130/202111300652.yLaNuuKr-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project df08b2fe8b35cb63dfb3b49738a3494b9b4e6f8e)
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/88ea43d691b0980bf49b4e579c39303cf3c9cd72
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Jeff-Xie/trace-Introduce-objtrace-trigger-to-trace-the-kernel-object/20211130-041958
        git checkout 88ea43d691b0980bf49b4e579c39303cf3c9cd72
        # 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=i386 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_object.c:518:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (WARN_ON_ONCE(atomic_read(&trace_object_ref) <= 0))
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/asm-generic/bug.h:179:33: note: expanded from macro 'WARN_ON_ONCE'
   #define WARN_ON_ONCE(condition) WARN_ON(condition)
                                   ^~~~~~~~~~~~~~~~~~
   include/asm-generic/bug.h:165:28: note: expanded from macro 'WARN_ON'
   #define WARN_ON(condition) ({                                           \
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_object.c:533:9: note: uninitialized use occurs here
           return ret;
                  ^~~
   kernel/trace/trace_object.c:518:2: note: remove the 'if' if its condition is always false
           if (WARN_ON_ONCE(atomic_read(&trace_object_ref) <= 0))
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_object.c:516:9: note: initialize the variable 'ret' to silence this warning
           int ret;
                  ^
                   = 0
   1 warning generated.


vim +518 kernel/trace/trace_object.c

   513	
   514	static int exit_trace_object(void)
   515	{
   516		int ret;
   517	
 > 518		if (WARN_ON_ONCE(atomic_read(&trace_object_ref) <= 0))

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