tree: https://android.googlesource.com/kernel/common android-mainline-tracking head: 21cd061cbda4ef6b2ba3dfb3ef4b076e0103c8f1 commit: f75d594f773d9130918bb19df7a78fbfd1c68b8e [229/682] ANDROID: usb: gadget: f_audio_source: New gadget driver for audio output config: x86_64-randconfig-r004-20201014 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project e7fe3c6dfede8d5781bd000741c3dea7088307a4) 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 # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git remote add android-common https://android.googlesource.com/kernel/common git fetch --no-tags android-common android-mainline-tracking git checkout f75d594f773d9130918bb19df7a78fbfd1c68b8e # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): int audio_source_bind_config(struct usb_configuration *c, ^ drivers/usb/gadget/function/f_audio_source.c:863:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int audio_source_bind_config(struct usb_configuration *c, ^ static 1 warning generated. vim +/audio_source_bind_config +863 drivers/usb/gadget/function/f_audio_source.c 862 864 struct audio_source_config *config) 865 { 866 struct audio_dev *audio; 867 int err; 868 869 config->card = -1; 870 config->device = -1; 871 872 audio = &_audio_dev; 873 874 err = snd_card_setup(c, config); 875 if (err) 876 return err; 877 878 err = usb_add_function(c, &audio->func); 879 if (err) 880 goto add_fail; 881 882 return 0; 883 884 add_fail: 885 snd_card_free(audio->card); 886 return err; 887 } 888 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org