Hi Dirk, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.4.y head: ccba204bf567bf5349e9635ea1fb8cd18d23c123 commit: 35b34d264cb347909ec89d9fa895900035d5438c [4066/4470] scripts/dtc: Remove redundant YYLOC global declaration config: arm64-defconfig (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project bee6c234ed28ae7349cb83afa322dfd8394590ee) reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu git checkout 35b34d264cb347909ec89d9fa895900035d5438c # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): */ mutex_lock(&dev->struct_mutex); ^ drivers/gpu/drm/drm_lock.c:357:2: note: previous statement is here if (!drm_core_check_feature(dev, DRIVER_LEGACY)) ^ 1 warning generated. vim +/if +363 drivers/gpu/drm/drm_lock.c 058ca50ce3f1d4 Dave Airlie 2019-04-23 354 058ca50ce3f1d4 Dave Airlie 2019-04-23 355 void drm_legacy_lock_master_cleanup(struct drm_device *dev, struct drm_master *master) 058ca50ce3f1d4 Dave Airlie 2019-04-23 356 { 058ca50ce3f1d4 Dave Airlie 2019-04-23 357 if (!drm_core_check_feature(dev, DRIVER_LEGACY)) 058ca50ce3f1d4 Dave Airlie 2019-04-23 358 return; 058ca50ce3f1d4 Dave Airlie 2019-04-23 359 058ca50ce3f1d4 Dave Airlie 2019-04-23 360 /* 058ca50ce3f1d4 Dave Airlie 2019-04-23 361 * Since the master is disappearing, so is the 058ca50ce3f1d4 Dave Airlie 2019-04-23 362 * possibility to lock. 058ca50ce3f1d4 Dave Airlie 2019-04-23 @363 */ mutex_lock(&dev->struct_mutex); :::::: The code at line 363 was first introduced by commit :::::: 058ca50ce3f1d40dac4d918a91684b0af4a0c468 drm/legacy: move lock cleanup for master into lock file (v2) :::::: TO: Dave Airlie <airlied(a)redhat.com&gt; :::::: CC: Dave Airlie <airlied(a)redhat.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org