Messages in this thread | | | Subject | Re: kernel/sched/core.c:5854:20: warning: unused function 'sched_core_cpu_deactivate' | From | Nathan Chancellor <> | Date | Thu, 2 Sep 2021 11:27:06 -0700 |
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On 9/2/2021 11:21 AM, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > head: 4a3bb4200a5958d76cc26ebe4db4257efa56812b > commit: 3c474b3239f12fe0b00d7e82481f36a1f31e79ab sched: Fix Core-wide rq->lock for uninitialized CPUs > date: 13 days ago > config: mips-randconfig-r004-20210902 (attached as .config) > compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c9948e9254fbb6ea00f66c7b4542311d21e060be) > 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 mips cross compiling tool for clang build > # apt-get install binutils-mips-linux-gnu > # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3c474b3239f12fe0b00d7e82481f36a1f31e79ab > git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > git fetch --no-tags linus master > git checkout 3c474b3239f12fe0b00d7e82481f36a1f31e79ab > # save the attached .config to linux build tree > mkdir build_dir > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=mips SHELL=/bin/bash kernel/sched/ > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp@intel.com> > > All warnings (new ones prefixed by >>): > > kernel/sched/core.c:3272:20: warning: unused function 'rq_has_pinned_tasks' > static inline bool rq_has_pinned_tasks(struct rq > ^ > kernel/sched/core.c:5123:20: warning: unused function 'sched_tick_start' > static inline void sched_tick_start(int cpu) { } > ^ > kernel/sched/core.c:5124:20: warning: unused function 'sched_tick_stop' > static inline void sched_tick_stop(int cpu) { } > ^ > kernel/sched/core.c:5853:20: warning: unused function 'sched_core_cpu_starting' > static inline void sched_core_cpu_starting(unsigned int cpu) {} > ^ >>> kernel/sched/core.c:5854:20: warning: unused function 'sched_core_cpu_deactivate' > static inline void sched_core_cpu_deactivate(unsigned int cpu) {} > ^ >>> kernel/sched/core.c:5855:20: warning: unused function 'sched_core_cpu_dying' > static inline void sched_core_cpu_dying(unsigned int cpu) {} > ^ > fatal error: error in backend: Nested variants found in inline asm string: ' .set push > .set noat > .set push > .set arch=r4000 > .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/cmpxchg.h", .line = 163, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif > 1: ll $0, $2 # __cmpxchg_asm > bne $0, ${3:z}, 2f > .set pop > move $$1, ${4:z} > .set arch=r4000 > sc $$1, $1 > beqz $$1, 1b > .set pop > 2: .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/cmpxchg.h", .line = 163, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif > ' > clang-14: error: clang frontend command failed with exit code 70 (use -v to see invocation) > clang version 14.0.0 (git://gitmirror/llvm_project c9948e9254fbb6ea00f66c7b4542311d21e060be) > Target: mipsel-unknown-linux > Thread model: posix > InstalledDir: /opt/cross/clang-c9948e9254/bin > clang-14: note: diagnostic msg: > Makefile arch include kernel mm nr_bisected scripts source usr > > > vim +/sched_core_cpu_deactivate +5854 kernel/sched/core.c > > 5852 > 5853 static inline void sched_core_cpu_starting(unsigned int cpu) {} >> 5854 static inline void sched_core_cpu_deactivate(unsigned int cpu) {} >> 5855 static inline void sched_core_cpu_dying(unsigned int cpu) {} > 5856
Is there any way for the test robot to ignore -Wunused-function warnings for stub functions? Masahiro purposefully wanted these warnings shown for static inline functions after commit 6863f5643dd7 ("kbuild: allow Clang to find unused static inline functions for W=1 build") but the entire point of the stub functions is that there should be no warnings ever (even though I know this is a W=1 build but still...).
Cheers, Nathan
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