tree: https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git test/usb-hacks-wip head: 8d9dd7caccc6daebab8b2a1a7bbd09e605b83fba commit: ca31918f6843b5369d0c900c43bfe5f71441b5b2 [44/53] ALSA: usb-audio: Refactor endpoint management config: x86_64-randconfig-a001-20201115 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 9a85643cd357e412cff69067bb5c4840e228c2ab) 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 # https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/commit/?i... git remote add sound https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git git fetch --no-tags sound test/usb-hacks-wip git checkout ca31918f6843b5369d0c900c43bfe5f71441b5b2 # 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 snd_usb_sync_endpoint_start(struct snd_usb_endpoint *ep, ^ sound/usb/endpoint.c:1255:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int snd_usb_sync_endpoint_start(struct snd_usb_endpoint *ep, ^ static void snd_usb_sync_endpoint_stop(struct snd_usb_endpoint *ep) ^ sound/usb/endpoint.c:1298:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void snd_usb_sync_endpoint_stop(struct snd_usb_endpoint *ep) ^ static 2 warnings generated. vim +/snd_usb_sync_endpoint_start +1255 sound/usb/endpoint.c 1254 1256 struct snd_usb_endpoint *data_ep) 1257 { 1258 int err; 1259 1260 err = snd_usb_endpoint_start(ep); 1261 return err; 1262 } 1263 1264 /** 1265 * snd_usb_endpoint_stop: stop an snd_usb_endpoint 1266 * 1267 * @ep: the endpoint to stop (may be NULL) 1268 * 1269 * A call to this function will decrement the use count of the endpoint. 1270 * In case the last user has requested the endpoint stop, the URBs will 1271 * actually be deactivated. 1272 * 1273 * Must be balanced to calls of snd_usb_endpoint_start(). 1274 * 1275 * The caller needs to synchronize the pending stop operation via 1276 * snd_usb_endpoint_sync_pending_stop(). 1277 */ 1278 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep) 1279 { 1280 if (!ep) 1281 return; 1282 1283 usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (count %d)\n", 1284 ep_type_name(ep->type), ep->ep_num, ep->use_count); 1285 1286 if (snd_BUG_ON(ep->use_count == 0)) 1287 return; 1288 1289 if (ep->sync_master) 1290 WRITE_ONCE(ep->sync_master->sync_slave, NULL); 1291 1292 if (--ep->use_count == 0) { 1293 deactivate_urbs(ep, false); 1294 set_bit(EP_FLAG_STOPPING, &ep->flags); 1295 } 1296 } 1297 1299 { 1300 snd_usb_endpoint_stop(ep); 1301 } 1302 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org