tree: https://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux.git kgdb/for-next head: 3dc6a1ac3f70f1e4530132bd231599e0a91d5b5d commit: eae3e19ca930a56c726fbf4dc3adc198b8f5d61d [9/14] kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc config: x86_64-allmodconfig (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 135b877874fae96b4372c8a3fbfaa8ff44ff86e3) reproduce: 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 checkout eae3e19ca930a56c726fbf4dc3adc198b8f5d61d # 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: kbuild test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>, old ones prefixed by <<): >> drivers/tty/serial/kgdboc.c:410:13: error: expected parameter declarator early_param("ekgdboc", kgdboc_early_init); ^ >> drivers/tty/serial/kgdboc.c:410:13: error: expected ')' drivers/tty/serial/kgdboc.c:410:12: note: to match this '(' early_param("ekgdboc", kgdboc_early_init); ^ >> drivers/tty/serial/kgdboc.c:410:1: warning: declaration specifier missing, defaulting to 'int' early_param("ekgdboc", kgdboc_early_init); ^ int >> drivers/tty/serial/kgdboc.c:410:12: error: this function declaration is not a prototype [-Werror,-Wstrict-prototypes] early_param("ekgdboc", kgdboc_early_init); ^ void 1 warning and 3 errors generated. vim +410 drivers/tty/serial/kgdboc.c 9731191f75a54c4 drivers/serial/kgdboc.c Jason Wessel 2010-05-20 409 9731191f75a54c4 drivers/serial/kgdboc.c Jason Wessel 2010-05-20 @410 early_param("ekgdboc", kgdboc_early_init); 9731191f75a54c4 drivers/serial/kgdboc.c Jason Wessel 2010-05-20 411 :::::: The code at line 410 was first introduced by commit :::::: 9731191f75a54c4fa17e9b9b88f3144cf4b47836 kgdboc: Add ekgdboc for early use of the kernel debugger :::::: TO: Jason Wessel <jason.wessel(a)windriver.com&gt; :::::: CC: Jason Wessel <jason.wessel(a)windriver.com&gt;