tree: https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git testing/clang/fallthrough head: d16b79b21df4c592423c69b59b31a6a9ec6b0fd6 commit: 09b39705b81484347c7561a5528e08b2a70e67a6 [1/2] Revert "kbuild: Do not enable -Wimplicit-fallthrough for clang for now" config: mips-randconfig-r016-20201111 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project a7b65741441556d295079fc4f2391d99fd1c1111) 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 mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/comm... git remote add gustavoars-linux https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git git fetch --no-tags gustavoars-linux testing/clang/fallthrough git checkout 09b39705b81484347c7561a5528e08b2a70e67a6 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips 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 >>): default: ^ arch/mips/kernel/uprobes.c:176:2: note: insert 'break;' to avoid fall-through default: ^ break; 1 warning generated. vim +176 arch/mips/kernel/uprobes.c 40e084a506eba78 Ralf Baechle 2015-07-29 153 40e084a506eba78 Ralf Baechle 2015-07-29 154 int arch_uprobe_exception_notify(struct notifier_block *self, 40e084a506eba78 Ralf Baechle 2015-07-29 155 unsigned long val, void *data) 40e084a506eba78 Ralf Baechle 2015-07-29 156 { 40e084a506eba78 Ralf Baechle 2015-07-29 157 struct die_args *args = data; 40e084a506eba78 Ralf Baechle 2015-07-29 158 struct pt_regs *regs = args->regs; 40e084a506eba78 Ralf Baechle 2015-07-29 159 40e084a506eba78 Ralf Baechle 2015-07-29 160 /* regs == NULL is a kernel bug */ 40e084a506eba78 Ralf Baechle 2015-07-29 161 if (WARN_ON(!regs)) 40e084a506eba78 Ralf Baechle 2015-07-29 162 return NOTIFY_DONE; 40e084a506eba78 Ralf Baechle 2015-07-29 163 40e084a506eba78 Ralf Baechle 2015-07-29 164 /* We are only interested in userspace traps */ 40e084a506eba78 Ralf Baechle 2015-07-29 165 if (!user_mode(regs)) 40e084a506eba78 Ralf Baechle 2015-07-29 166 return NOTIFY_DONE; 40e084a506eba78 Ralf Baechle 2015-07-29 167 40e084a506eba78 Ralf Baechle 2015-07-29 168 switch (val) { 2809328f6ef2139 Marcin Nowakowski 2016-08-11 169 case DIE_UPROBE: 40e084a506eba78 Ralf Baechle 2015-07-29 170 if (uprobe_pre_sstep_notifier(regs)) 40e084a506eba78 Ralf Baechle 2015-07-29 171 return NOTIFY_STOP; 40e084a506eba78 Ralf Baechle 2015-07-29 172 break; 40e084a506eba78 Ralf Baechle 2015-07-29 173 case DIE_UPROBE_XOL: 40e084a506eba78 Ralf Baechle 2015-07-29 174 if (uprobe_post_sstep_notifier(regs)) 40e084a506eba78 Ralf Baechle 2015-07-29 175 return NOTIFY_STOP; 40e084a506eba78 Ralf Baechle 2015-07-29 @176 default: 40e084a506eba78 Ralf Baechle 2015-07-29 177 break; 40e084a506eba78 Ralf Baechle 2015-07-29 178 } 40e084a506eba78 Ralf Baechle 2015-07-29 179 40e084a506eba78 Ralf Baechle 2015-07-29 180 return 0; 40e084a506eba78 Ralf Baechle 2015-07-29 181 } 40e084a506eba78 Ralf Baechle 2015-07-29 182 :::::: The code at line 176 was first introduced by commit :::::: 40e084a506eba78310cd5e8ab700fd1226c6130a MIPS: Add uprobes support. :::::: TO: Ralf Baechle <ralf(a)linux-mips.org&gt; :::::: CC: Ralf Baechle <ralf(a)linux-mips.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org