Hi Zhang, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on next-20221031] url: https://github.com/intel-lab-lkp/linux/commits/Zhang-Qiao/sched-sched_fork-optimizations/20221031-202427 patch link: https://lore.kernel.org/r/20221031125113.72980-2-zhangqiao22%40huawei.com patch subject: [PATCH next 1/2] sched: Init new task's vruntime after select cpu config: hexagon-randconfig-r006-20221101 compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 791a7ae1ba3efd6bca96338e10ffde557ba83920) 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://github.com/intel-lab-lkp/linux/commit/dd85b689329a85b7c34067d160a67569c82327c6 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Zhang-Qiao/sched-sched_fork-optimizations/20221031-202427 git checkout dd85b689329a85b7c34067d160a67569c82327c6 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash kernel/sched/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot All warnings (new ones prefixed by >>): In file included from kernel/sched/core.c:9: In file included from include/linux/highmem.h:12: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from kernel/sched/core.c:9: In file included from include/linux/highmem.h:12: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from kernel/sched/core.c:9: In file included from include/linux/highmem.h:12: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ >> kernel/sched/core.c:4654:6: warning: no previous prototype for function 'sched_task_fork' [-Wmissing-prototypes] void sched_task_fork(struct task_struct *p) ^ kernel/sched/core.c:4654:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void sched_task_fork(struct task_struct *p) ^ static kernel/sched/core.c:3579:20: warning: unused function 'rq_has_pinned_tasks' [-Wunused-function] static inline bool rq_has_pinned_tasks(struct rq *rq) ^ kernel/sched/core.c:5645:20: warning: unused function 'sched_tick_start' [-Wunused-function] static inline void sched_tick_start(int cpu) { } ^ kernel/sched/core.c:5646:20: warning: unused function 'sched_tick_stop' [-Wunused-function] static inline void sched_tick_stop(int cpu) { } ^ kernel/sched/core.c:6340:20: warning: unused function 'sched_core_cpu_starting' [-Wunused-function] static inline void sched_core_cpu_starting(unsigned int cpu) {} ^ kernel/sched/core.c:6341:20: warning: unused function 'sched_core_cpu_deactivate' [-Wunused-function] static inline void sched_core_cpu_deactivate(unsigned int cpu) {} ^ kernel/sched/core.c:6342:20: warning: unused function 'sched_core_cpu_dying' [-Wunused-function] static inline void sched_core_cpu_dying(unsigned int cpu) {} ^ 13 warnings generated. vim +/sched_task_fork +4654 kernel/sched/core.c 4653 > 4654 void sched_task_fork(struct task_struct *p) 4655 { 4656 if (p->sched_class->task_fork) 4657 p->sched_class->task_fork(p); 4658 } 4659 -- 0-DAY CI Kernel Test Service https://01.org/lkp