Hi Ard, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 71941773e143369a73c9c4a3b62fbb60736a1182 commit: 41918ec82eb6f80c8b401422f27ca76c85aa0cb7 [4103/11953] ARM: ftrace: enable the graph tracer with the EABI unwinder config: arm-aspeed_g4_defconfig (https://download.01.org/0day-ci/archive/20220311/202203110903.3xDyTUVl-lkp@xxxxxxxxx/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 276ca87382b8f16a65bddac700202924228982f6) 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/next/linux-next.git/commit/?id=41918ec82eb6f80c8b401422f27ca76c85aa0cb7 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 41918ec82eb6f80c8b401422f27ca76c85aa0cb7 # 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/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): >> arch/arm/kernel/ftrace.c:229:6: warning: no previous prototype for function 'prepare_ftrace_return' [-Wmissing-prototypes] void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, ^ arch/arm/kernel/ftrace.c:229:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, ^ static 1 warning generated. vim +/prepare_ftrace_return +229 arch/arm/kernel/ftrace.c 376cfa8730c08c Tim Bird 2010-10-09 226 376cfa8730c08c Tim Bird 2010-10-09 227 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 228 asmlinkage 376cfa8730c08c Tim Bird 2010-10-09 @229 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 230 unsigned long frame_pointer, 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 231 unsigned long stack_pointer) 376cfa8730c08c Tim Bird 2010-10-09 232 { 376cfa8730c08c Tim Bird 2010-10-09 233 unsigned long return_hooker = (unsigned long) &return_to_handler; 376cfa8730c08c Tim Bird 2010-10-09 234 unsigned long old; 376cfa8730c08c Tim Bird 2010-10-09 235 376cfa8730c08c Tim Bird 2010-10-09 236 if (unlikely(atomic_read(¤t->tracing_graph_pause))) 376cfa8730c08c Tim Bird 2010-10-09 237 return; 376cfa8730c08c Tim Bird 2010-10-09 238 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 239 if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER)) { 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 240 /* FP points one word below parent's top of stack */ 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 241 frame_pointer += 4; 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 242 } else { 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 243 struct stackframe frame = { 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 244 .fp = frame_pointer, 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 245 .sp = stack_pointer, 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 246 .lr = self_addr, 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 247 .pc = self_addr, 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 248 }; 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 249 if (unwind_frame(&frame) < 0) 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 250 return; 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 251 if (frame.lr != self_addr) 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 252 parent = frame.lr_addr; 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 253 frame_pointer = frame.sp; 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 254 } 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 255 376cfa8730c08c Tim Bird 2010-10-09 256 old = *parent; 376cfa8730c08c Tim Bird 2010-10-09 257 *parent = return_hooker; 376cfa8730c08c Tim Bird 2010-10-09 258 f1f5b14afd7cce Steven Rostedt (VMware 2018-11-18 259) if (function_graph_enter(old, self_addr, frame_pointer, NULL)) 376cfa8730c08c Tim Bird 2010-10-09 260 *parent = old; 376cfa8730c08c Tim Bird 2010-10-09 261 } dd686eb13959e4 Rabin Vincent 2010-11-06 262 :::::: The code at line 229 was first introduced by commit :::::: 376cfa8730c08c0394d0aa1d4a80fd8c9971f323 ARM: ftrace: function graph tracer support :::::: TO: Tim Bird <tim.bird@xxxxxxxxxxx> :::::: CC: Rabin Vincent <rabin@xxxxxx> --- 0-DAY CI Kernel Test Service https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
