tree: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-5.16.y-rt-rebase head: 1722f531f5244c70dcd9687c40729860bb254e8d commit: e1fd5438186d729df636919574f08231f7ecdd1d [16/132] serial: 8250: implement write_atomic config: arm-randconfig-r016-20220121 (https://download.01.org/0day-ci/archive/20220122/202201220837.EAj9Nrqa-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 7b3d30728816403d1fd73cc5082e9fb761262bce) 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 arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/com... git remote add rt-devel https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git git fetch --no-tags rt-devel linux-5.16.y-rt-rebase git checkout e1fd5438186d729df636919574f08231f7ecdd1d # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash kernel/printk/ 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 >>): bool any_usable = false; ^ 1 warning generated. vim +/any_usable +2979 kernel/printk/printk.c fe3d8ad31cf51b kernel/printk.c Feng Tang 2011-03-22 2975 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2976 #ifdef CONFIG_HAVE_ATOMIC_CONSOLE 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2977 static void atomic_console_flush_all(void) 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2978 { 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 @2979 bool any_usable = false; 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2980 unsigned long flags; 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2981 struct console *con; 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2982 bool any_progress; 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2983 int index = 0; 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2984 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2985 if (console_suspended) 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2986 return; 02489ebe320634 kernel/printk/printk.c John Ogness 2021-12-22 2987 :::::: The code at line 2979 was first introduced by commit :::::: 02489ebe320634155c5ddb3110d7d456fa68d304 printk: add infrastucture for atomic consoles :::::: TO: John Ogness <john.ogness(a)linutronix.de&gt; :::::: CC: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org