tree: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git ftrace/fgraph-multi head: 978dc256bd4d08df876d58b4fa01ba4cb3926242 commit: a436705d3d66255f8e32aa715dca3fcabe9cb0a9 [31/40] ftrace/function_graph: Pass fgraph_ops to function graph callbacks config: riscv-randconfig-r032-20210416 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 6a18cc23efad410db48a3ccfc233d215de7d4cb9) 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 riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git/c... git remote add trace https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git git fetch --no-tags trace ftrace/fgraph-multi git checkout a436705d3d66255f8e32aa715dca3fcabe9cb0a9 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=riscv If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): kernel/trace/fgraph.c:491:15: warning: no previous prototype for function 'ftrace_return_to_handler' [-Wmissing-prototypes] unsigned long ftrace_return_to_handler(unsigned long frame_pointer) ^ kernel/trace/fgraph.c:491:1: note: declare 'static' if the function is not intended to be used outside of this translation unit unsigned long ftrace_return_to_handler(unsigned long frame_pointer) ^ static kernel/trace/fgraph.c:635:6: warning: no previous prototype for function 'ftrace_graph_sleep_time_control' [-Wmissing-prototypes] void ftrace_graph_sleep_time_control(bool enable) ^ kernel/trace/fgraph.c:635:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void ftrace_graph_sleep_time_control(bool enable) ^ static trace_func_graph_ret_t ftrace_graph_return = ftrace_stub_graph; ^ ~~~~~~~~~~~~~~~~~ ftrace_graph_return = ftrace_stub_graph; ^ ~~~~~~~~~~~~~~~~~ 2 warnings and 2 errors generated. vim +647 kernel/trace/fgraph.c b83b43ffc6e4b5 Steven Rostedt (VMware 2019-10-15 645) e73e679f656e67 Steven Rostedt (VMware 2018-11-15 646) /* The callbacks that hook a function */ 46f9469247c6f4 Steven Rostedt (VMware 2019-11-18 @647) trace_func_graph_ret_t ftrace_graph_return = ftrace_stub_graph; e73e679f656e67 Steven Rostedt (VMware 2018-11-15 648) trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub; e73e679f656e67 Steven Rostedt (VMware 2018-11-15 649) :::::: The code at line 647 was first introduced by commit :::::: 46f9469247c6f4697cbbf37e4b3961120bf07f29 ftrace: Rename ftrace_graph_stub to ftrace_stub_graph :::::: TO: Steven Rostedt (VMware) <rostedt(a)goodmis.org&gt; :::::: CC: Steven Rostedt (VMware) <rostedt(a)goodmis.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org