Hi Ard, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 2a987e65025e2b79c6d453b78cb5985ac6e5eb26 commit: 4d576cab16f57e1f87978f6997a725179398341e ARM: 9028/1: disable KASAN in call stack capturing routines date: 1 year ago config: arm-randconfig-c002-20211209 (https://download.01.org/0day-ci/archive/20211209/202112092330.MRS9Xygy-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 097a1cb1d5ebb3a0ec4bcaed8ba3ff6a8e33c00a) 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/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 4d576cab16f57e1f87978f6997a725179398341e # 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 arch/arm/kernel/ drivers/media/platform/ 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 >>): arch/arm/kernel/traps.c:82:6: warning: no previous prototype for function 'dump_backtrace_stm' [-Wmissing-prototypes] void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl) ^ arch/arm/kernel/traps.c:82:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl) ^ static arch/arm/kernel/traps.c:445:17: warning: no previous prototype for function 'do_undefinstr' [-Wmissing-prototypes] asmlinkage void do_undefinstr(struct pt_regs *regs) ^ arch/arm/kernel/traps.c:445:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage void do_undefinstr(struct pt_regs *regs) ^ static arch/arm/kernel/traps.c:510:39: warning: no previous prototype for function 'handle_fiq_as_nmi' [-Wmissing-prototypes] asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) ^ arch/arm/kernel/traps.c:510:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) ^ static arch/arm/kernel/traps.c:529:17: warning: no previous prototype for function 'bad_mode' [-Wmissing-prototypes] asmlinkage void bad_mode(struct pt_regs *regs, int reason) ^ arch/arm/kernel/traps.c:529:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage void bad_mode(struct pt_regs *regs, int reason) ^ static arch/arm/kernel/traps.c:602:16: warning: no previous prototype for function 'arm_syscall' [-Wmissing-prototypes] asmlinkage int arm_syscall(int no, struct pt_regs *regs) ^ arch/arm/kernel/traps.c:602:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage int arm_syscall(int no, struct pt_regs *regs) ^ static arch/arm/kernel/traps.c:728:1: warning: no previous prototype for function 'baddataabort' [-Wmissing-prototypes] baddataabort(int code, unsigned long instr, struct pt_regs *regs) ^ arch/arm/kernel/traps.c:727:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage void ^ static arch/arm/kernel/traps.c:768:17: warning: no previous prototype for function '__div0' [-Wmissing-prototypes] asmlinkage void __div0(void) ^ arch/arm/kernel/traps.c:768:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage void __div0(void) ^ static void abort(void) ^ arch/arm/kernel/traps.c:775:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void abort(void) ^ static arch/arm/kernel/traps.c:783:13: warning: no previous prototype for function 'trap_init' [-Wmissing-prototypes] void __init trap_init(void) ^ arch/arm/kernel/traps.c:783:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init trap_init(void) ^ static 9 warnings generated. vim +/abort +775 arch/arm/kernel/traps.c ^1da177e4c3f41 Linus Torvalds 2005-04-16 767 ^1da177e4c3f41 Linus Torvalds 2005-04-16 @768 asmlinkage void __div0(void) ^1da177e4c3f41 Linus Torvalds 2005-04-16 769 { 4ed89f22280614 Russell King 2014-10-28 770 pr_err("Division by zero in kernel.\n"); ^1da177e4c3f41 Linus Torvalds 2005-04-16 771 dump_stack(); ^1da177e4c3f41 Linus Torvalds 2005-04-16 772 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 773 EXPORT_SYMBOL(__div0); ^1da177e4c3f41 Linus Torvalds 2005-04-16 774 ^1da177e4c3f41 Linus Torvalds 2005-04-16 @775 void abort(void) ^1da177e4c3f41 Linus Torvalds 2005-04-16 776 { ^1da177e4c3f41 Linus Torvalds 2005-04-16 777 BUG(); ^1da177e4c3f41 Linus Torvalds 2005-04-16 778 ^1da177e4c3f41 Linus Torvalds 2005-04-16 779 /* if that doesn't kill us, halt */ ^1da177e4c3f41 Linus Torvalds 2005-04-16 780 panic("Oops failed to kill thread"); ^1da177e4c3f41 Linus Torvalds 2005-04-16 781 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 782 :::::: The code at line 775 was first introduced by commit :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2 :::::: TO: Linus Torvalds <torvalds(a)ppc970.osdl.org&gt; :::::: CC: Linus Torvalds <torvalds(a)ppc970.osdl.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org