kernel/sched/core.c:6854:20: warning: unused function 'balance_hotplug_wait'

kernel test robot
2021-10-11T06:49:10Z

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Hi Thomas,

FYI, the error/warning still remains.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 64570fbc14f8d7cb3fe3995f20e26bc25ce4b2cc
commit: 1cf12e08bc4d50a76b80c42a3109c53d8794a0c9 sched/hotplug: Consolidate task migration on CPU unplug
date: 11 months ago
config: mips-randconfig-r012-20211011 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 903b30fea21f99d8f48fde4defcc838970e30ee1)
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=1cf12e08bc4d50a76b80c42a3109c53d8794a0c9
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 1cf12e08bc4d50a76b80c42a3109c53d8794a0c9
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 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:2376:6: warning: no previous prototype for function 'sched_set_stop_task'
void sched_set_stop_task(int cpu, struct task_struct
^
kernel/sched/core.c:2376:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void sched_set_stop_task(int cpu, struct task_struct
^
static
kernel/sched/core.c:3746:13: warning: variable 'rq' set but not used
struct rq
^
kernel/sched/core.c:324:1: warning: unused function 'rq_csd_init'
rq_csd_init(struct rq call_single_data_t smp_call_func_t func)
^
kernel/sched/core.c:4196:20: warning: unused function 'sched_tick_stop'
static inline void sched_tick_stop(int cpu) { }
^
>> kernel/sched/core.c:6854:20: warning: unused function 'balance_hotplug_wait'
static inline void balance_hotplug_wait(void)
^
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 f95d9c95bbf4cf662b9a181245fc6dcede39f590)
Target: mipsel-unknown-linux
Thread model: posix
InstalledDir: /opt/cross/clang-f95d9c95bb/bin
clang-14: note: diagnostic msg:
Makefile arch include kernel scripts source usr

vim +/balance_hotplug_wait +6854 kernel/sched/core.c

2558aacff8586699 Peter Zijlstra 2020-09-11 6853
f2469a1fb43f85d2 Thomas Gleixner 2020-09-14 @6854 static inline void balance_hotplug_wait(void)
f2469a1fb43f85d2 Thomas Gleixner 2020-09-14 6855 {
f2469a1fb43f85d2 Thomas Gleixner 2020-09-14 6856 }
f2469a1fb43f85d2 Thomas Gleixner 2020-09-14 6857

:::::: The code at line 6854 was first introduced by commit
:::::: f2469a1fb43f85d243ce72638367fb6e15c33491 sched/core: Wait for tasks being pushed away on hotplug

:::::: TO: Thomas Gleixner <tglx@linutronix.de>
:::::: CC: Peter Zijlstra <peterz@infradead.org>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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