tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: fd8dab197cca2746e1fcd399a218eec5164726d4 commit: 8107f00bdd7c0e63e47890963c4a28f215e2d437 [2671/4127] kbuild: treat char as always unsigned config: mips-pic32mzda_defconfig compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 791a7ae1ba3efd6bca96338e10ffde557ba83920) 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-mipsel-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=8107f00bdd7c0e63e47890963c4a28f215e2d437 git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 8107f00bdd7c0e63e47890963c4a28f215e2d437 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash arch/mips/pic32/pic32mzda/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> arch/mips/pic32/pic32mzda/early_console.c:141:11: warning: result of comparison of constant -1 with expression of type 'char' is always false [-Wtautological-constant-out-of-range-compare] if (port == -1) ~~~~ ^ ~~ arch/mips/pic32/pic32mzda/early_console.c:144:11: warning: result of comparison of constant -1 with expression of type 'char' is always false [-Wtautological-constant-out-of-range-compare] if (port == -1) ~~~~ ^ ~~ 2 warnings generated. vim +/char +141 arch/mips/pic32/pic32mzda/early_console.c 2572f00db8a68b Joshua Henderson 2016-01-13 132 2572f00db8a68b Joshua Henderson 2016-01-13 133 void __init fw_init_early_console(char port) 2572f00db8a68b Joshua Henderson 2016-01-13 134 { 2572f00db8a68b Joshua Henderson 2016-01-13 135 char *arch_cmdline = pic32_getcmdline(); 2572f00db8a68b Joshua Henderson 2016-01-13 136 int baud = -1; 2572f00db8a68b Joshua Henderson 2016-01-13 137 4bdc0d676a6431 Christoph Hellwig 2020-01-06 138 uart_base = ioremap(PIC32_BASE_UART, 0xc00); 2572f00db8a68b Joshua Henderson 2016-01-13 139 2572f00db8a68b Joshua Henderson 2016-01-13 140 baud = get_baud_from_cmdline(arch_cmdline); 2572f00db8a68b Joshua Henderson 2016-01-13 @141 if (port == -1) 2572f00db8a68b Joshua Henderson 2016-01-13 142 port = get_port_from_cmdline(arch_cmdline); 2572f00db8a68b Joshua Henderson 2016-01-13 143 2572f00db8a68b Joshua Henderson 2016-01-13 144 if (port == -1) 2572f00db8a68b Joshua Henderson 2016-01-13 145 port = EARLY_CONSOLE_PORT; 2572f00db8a68b Joshua Henderson 2016-01-13 146 2572f00db8a68b Joshua Henderson 2016-01-13 147 if (baud == -1) 2572f00db8a68b Joshua Henderson 2016-01-13 148 baud = EARLY_CONSOLE_BAUDRATE; 2572f00db8a68b Joshua Henderson 2016-01-13 149 2572f00db8a68b Joshua Henderson 2016-01-13 150 setup_early_console(port, baud); 2572f00db8a68b Joshua Henderson 2016-01-13 151 } 2572f00db8a68b Joshua Henderson 2016-01-13 152 :::::: The code at line 141 was first introduced by commit :::::: 2572f00db8a68bb46001678c1c98ad8b70e04b31 MIPS: Add support for PIC32MZDA platform :::::: TO: Joshua Henderson :::::: CC: Ralf Baechle -- 0-DAY CI Kernel Test Service https://01.org/lkp