Hi Peter,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   2734d6c1b1a089fb593ef6a23d4b70903526fe0c
commit: 9edeaea1bc452372718837ed2ba775811baf1ba1 sched: Core-wide rq->lock
date:   10 weeks ago
config: mips-randconfig-r006-20210720 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 87039c048c0cbc3d8cbba86187269b006bf2f373)
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=9edeaea1bc452372718837ed2ba775811baf1ba1
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 9edeaea1bc452372718837ed2ba775811baf1ba1
        # 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:5467:35: warning: no previous prototype for function 'schedule_user'
   asmlinkage __visible void __sched schedule_user(void)
   ^
   kernel/sched/core.c:5467:22: note: declare 'static' if the function is not intended to be used outside of this translation unit
   asmlinkage __visible void __sched schedule_user(void)
   ^
   static
   kernel/sched/core.c:3080:20: warning: unused function 'rq_has_pinned_tasks'
   static inline bool rq_has_pinned_tasks(struct rq
   ^
   kernel/sched/core.c:4941:20: warning: unused function 'sched_tick_start'
   static inline void sched_tick_start(int cpu) { }
   ^
   kernel/sched/core.c:4942:20: warning: unused function 'sched_tick_stop'
   static inline void sched_tick_stop(int cpu) { }
   ^
>> kernel/sched/core.c:5190:20: warning: unused function 'sched_core_cpu_starting'
   static inline void sched_core_cpu_starting(unsigned int cpu) {}
   ^
   fatal error: error in backend: Nested variants found in inline asm string: ' .set push
   .set mips64r2
   .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/atomic.h", .line = 153, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif
   1: ll $1, $2 # atomic_fetch_add
   addu $0, $1, $3
   sc $0, $2
   beqz $0, 1b
   .set pop
   move $0, $1
   '
   clang-13: error: clang frontend command failed with exit code 70 (use -v to see invocation)
   clang version 13.0.0 (git://gitmirror/llvm_project 87039c048c0cbc3d8cbba86187269b006bf2f373)
   Target: mipsel-unknown-linux-gnu
   Thread model: posix
   InstalledDir: /opt/cross/clang-87039c048c/bin
   clang-13: note: diagnostic msg:
   Makefile arch include kernel scripts source usr


vim +/sched_core_cpu_starting +5190 kernel/sched/core.c

  5189	
> 5190	static inline void sched_core_cpu_starting(unsigned int cpu) {}
  5191	

---
0-DAY CI Kernel Test Service, Intel Corporation
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