tree: https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git coresched head: 96c7e148eeff83b159e8e4c6d5aa9bed6ea47580 commit: f9ce34d192fc4b26bcb6402f41e534f1776d3832 [2/13] kernel/entry: Add support for core-wide protection of kernel-mode config: s390-randconfig-r012-20210115 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 5b42fd8dd4e7e29125a09a41a33af7c9cb57d144) 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 s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/commit/?i... git remote add jfern https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git git fetch --no-tags jfern coresched git checkout f9ce34d192fc4b26bcb6402f41e534f1776d3832 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:21:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \ ^ In file included from kernel/sched/core.c:13: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:490:61: 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/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:22:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0xff000000UL) >> 24))) ^ In file included from kernel/sched/core.c:13: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:490:61: 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/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:120:12: note: expanded from macro '__swab32' __fswab32(x)) ^ In file included from kernel/sched/core.c:13: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:501:33: 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:511:59: 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:521:59: 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); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ kernel/sched/core.c:283:6: warning: no previous prototype for function 'sched_core_get' [-Wmissing-prototypes] void sched_core_get(void) ^ kernel/sched/core.c:283:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void sched_core_get(void) ^ static kernel/sched/core.c:291:6: warning: no previous prototype for function 'sched_core_put' [-Wmissing-prototypes] void sched_core_put(void) ^ kernel/sched/core.c:291:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void sched_core_put(void) ^ static kernel/sched/core.c:3032:6: warning: no previous prototype for function 'sched_set_stop_task' [-Wmissing-prototypes] void sched_set_stop_task(int cpu, struct task_struct *stop) ^ kernel/sched/core.c:3032:1: 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 *stop) ^ static ti_check &= ~_TIF_UNSAFE_RET; ^ 23 warnings and 1 error generated. vim +/_TIF_UNSAFE_RET +5147 kernel/sched/core.c 5128 5129 /* 5130 * sched_core_wait_till_safe - Pause the caller's hyperthread until the core 5131 * exits the core-wide unsafe state. Obviously the CPU calling this function 5132 * should not be responsible for the core being in the core-wide unsafe state 5133 * otherwise it will deadlock. 5134 * 5135 * @ti_check: We spin here with IRQ enabled and preempt disabled. Break out of 5136 * the loop if TIF flags are set and notify caller about it. 5137 * 5138 * IRQs should be disabled. 5139 */ 5140 bool sched_core_wait_till_safe(unsigned long ti_check) 5141 { 5142 bool restart = false; 5143 struct rq *rq; 5144 int cpu; 5145 5146 /* We clear the thread flag only at the end, so no need to check for it. */ 5148 5149 cpu = smp_processor_id(); 5150 rq = cpu_rq(cpu); 5151 5152 if (!sched_core_enabled(rq)) 5153 goto ret; 5154 5155 /* Down grade to allow interrupts to prevent stop_machine lockups.. */ 5156 preempt_disable(); 5157 local_irq_enable(); 5158 5159 /* 5160 * Wait till the core of this HT is not in an unsafe state. 5161 * 5162 * Pair with raw_spin_lock/unlock() in sched_core_unsafe_enter/exit(). 5163 */ 5164 while (smp_load_acquire(&rq->core->core_unsafe_nest) > 0) { 5165 cpu_relax(); 5166 if (READ_ONCE(current_thread_info()->flags) & ti_check) { 5167 restart = true; 5168 break; 5169 } 5170 } 5171 5172 /* Upgrade it back to the expectations of entry code. */ 5173 local_irq_disable(); 5174 preempt_enable(); 5175 5176 ret: 5177 if (!restart) 5178 clear_tsk_thread_flag(current, TIF_UNSAFE_RET); 5179 5180 return restart; 5181 } 5182 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org