[kbuild-all] arch/csky/kernel/ftrace.c:152:6: warning: no previous prototype for 'prepare_ftrace_return'

Hi Julian, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: ecf93431963a95c0f475921101bedc0dd62ec96d commit: 7d37cb2c912dc5c25ffac784a4f9b98c06c6bd08 lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS date: 4 months ago config: csky-randconfig-r026-20210816 (attached as .config) compiler: csky-linux-gcc (GCC) 11.2.0 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 # 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 7d37cb2c912dc5c25ffac784a4f9b98c06c6bd08 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=csky 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 >>): 152 | void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, | ^~~~~~~~~~~~~~~~~~~~~ Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for LOCKDEP Depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT && (FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) Selected by - PROVE_LOCKING && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT - LOCK_STAT && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT - DEBUG_LOCK_ALLOC && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT vim +/prepare_ftrace_return +152 arch/csky/kernel/ftrace.c 89a3927a775c0a Guo Ren 2020-02-18 150 d7950be145c84c Guo Ren 2018-12-15 151 #ifdef CONFIG_FUNCTION_GRAPH_TRACER d7950be145c84c Guo Ren 2018-12-15 @152 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, d7950be145c84c Guo Ren 2018-12-15 153 unsigned long frame_pointer) d7950be145c84c Guo Ren 2018-12-15 154 { d7950be145c84c Guo Ren 2018-12-15 155 unsigned long return_hooker = (unsigned long)&return_to_handler; d7950be145c84c Guo Ren 2018-12-15 156 unsigned long old; 230c77a5e92a29 Guo Ren 2018-12-09 157 d7950be145c84c Guo Ren 2018-12-15 158 if (unlikely(atomic_read(&current->tracing_graph_pause))) d7950be145c84c Guo Ren 2018-12-15 159 return; 230c77a5e92a29 Guo Ren 2018-12-09 160 d7950be145c84c Guo Ren 2018-12-15 161 old = *parent; 230c77a5e92a29 Guo Ren 2018-12-09 162 d7950be145c84c Guo Ren 2018-12-15 163 if (!function_graph_enter(old, self_addr, d7950be145c84c Guo Ren 2018-12-15 164 *(unsigned long *)frame_pointer, parent)) { d7950be145c84c Guo Ren 2018-12-15 165 /* d7950be145c84c Guo Ren 2018-12-15 166 * For csky-gcc function has sub-call: d7950be145c84c Guo Ren 2018-12-15 167 * subi sp, sp, 8 d7950be145c84c Guo Ren 2018-12-15 168 * stw r8, (sp, 0) d7950be145c84c Guo Ren 2018-12-15 169 * mov r8, sp d7950be145c84c Guo Ren 2018-12-15 170 * st.w r15, (sp, 0x4) d7950be145c84c Guo Ren 2018-12-15 171 * push r15 d7950be145c84c Guo Ren 2018-12-15 172 * jl _mcount d7950be145c84c Guo Ren 2018-12-15 173 * We only need set *parent for resume d7950be145c84c Guo Ren 2018-12-15 174 * d7950be145c84c Guo Ren 2018-12-15 175 * For csky-gcc function has no sub-call: d7950be145c84c Guo Ren 2018-12-15 176 * subi sp, sp, 4 d7950be145c84c Guo Ren 2018-12-15 177 * stw r8, (sp, 0) d7950be145c84c Guo Ren 2018-12-15 178 * mov r8, sp d7950be145c84c Guo Ren 2018-12-15 179 * push r15 d7950be145c84c Guo Ren 2018-12-15 180 * jl _mcount d7950be145c84c Guo Ren 2018-12-15 181 * We need set *parent and *(frame_pointer + 4) for resume, d7950be145c84c Guo Ren 2018-12-15 182 * because lr is resumed twice. d7950be145c84c Guo Ren 2018-12-15 183 */ d7950be145c84c Guo Ren 2018-12-15 184 *parent = return_hooker; d7950be145c84c Guo Ren 2018-12-15 185 frame_pointer += 4; d7950be145c84c Guo Ren 2018-12-15 186 if (*(unsigned long *)frame_pointer == old) d7950be145c84c Guo Ren 2018-12-15 187 *(unsigned long *)frame_pointer = return_hooker; d7950be145c84c Guo Ren 2018-12-15 188 } 230c77a5e92a29 Guo Ren 2018-12-09 189 } 28bb030f933344 Guo Ren 2019-03-01 190 :::::: The code at line 152 was first introduced by commit :::::: d7950be145c84ca5094c52bc1ad1e7f1893d0f19 csky: ftrace call graph supported. :::::: TO: Guo Ren <ren_guo(a)c-sky.com&gt; :::::: CC: Guo Ren <ren_guo(a)c-sky.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org