Hi Peter, [FYI, it's a private test report for your RFC patch.] [auto build test ERROR on tip/sched/core] [cannot apply to tip/master arnd-asm-generic/master linus/master tip/x86/asm tip/core/entry v5.15-rc2 next-20210917] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Peter-Oskolkov/sched-umcg-RFC-UMCG-patchset/20210918-020438 base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 2b214a488b2c83d63c99c71d054273c1c2c07027 config: um-allmodconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/6b02b0cfe54c356b941399cacf1c752d11cc3a00 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Peter-Oskolkov/sched-umcg-RFC-UMCG-patchset/20210918-020438 git checkout 6b02b0cfe54c356b941399cacf1c752d11cc3a00 # save the attached .config to linux build tree make W=1 ARCH=um If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): In file included from kernel/sched/umcg.c:15: kernel/sched/umcg_uaccess.h: In function 'cmpxchg_user_32_nosleep': >> kernel/sched/umcg_uaccess.h:92:2: error: implicit declaration of function '__uaccess_begin_nospec' [-Werror=implicit-function-declaration] 92 | __uaccess_begin_nospec(); | ^~~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +/__uaccess_begin_nospec +92 kernel/sched/umcg_uaccess.h 72323cc0a0d77f Peter Oskolkov 2021-09-17 73 72323cc0a0d77f Peter Oskolkov 2021-09-17 74 /** 72323cc0a0d77f Peter Oskolkov 2021-09-17 75 * cmpxchg_32_user_nosleep - compare_exchange 32-bit values 72323cc0a0d77f Peter Oskolkov 2021-09-17 76 * 72323cc0a0d77f Peter Oskolkov 2021-09-17 77 * Return: 72323cc0a0d77f Peter Oskolkov 2021-09-17 78 * 0 - OK 72323cc0a0d77f Peter Oskolkov 2021-09-17 79 * -EFAULT: memory access error 72323cc0a0d77f Peter Oskolkov 2021-09-17 80 * -EAGAIN: @expected did not match; consult @prev 72323cc0a0d77f Peter Oskolkov 2021-09-17 81 */ 72323cc0a0d77f Peter Oskolkov 2021-09-17 82 static inline int cmpxchg_user_32_nosleep(u32 __user *uaddr, u32 *old, u32 new) 72323cc0a0d77f Peter Oskolkov 2021-09-17 83 { 72323cc0a0d77f Peter Oskolkov 2021-09-17 84 int ret = -EFAULT; 72323cc0a0d77f Peter Oskolkov 2021-09-17 85 u32 __old = *old; 72323cc0a0d77f Peter Oskolkov 2021-09-17 86 72323cc0a0d77f Peter Oskolkov 2021-09-17 87 if (unlikely(!access_ok(uaddr, sizeof(*uaddr)))) 72323cc0a0d77f Peter Oskolkov 2021-09-17 88 return -EFAULT; 72323cc0a0d77f Peter Oskolkov 2021-09-17 89 72323cc0a0d77f Peter Oskolkov 2021-09-17 90 pagefault_disable(); 72323cc0a0d77f Peter Oskolkov 2021-09-17 91 72323cc0a0d77f Peter Oskolkov 2021-09-17 @92 __uaccess_begin_nospec(); 72323cc0a0d77f Peter Oskolkov 2021-09-17 93 ret = __try_cmpxchg_user_32(old, uaddr, __old, new); 72323cc0a0d77f Peter Oskolkov 2021-09-17 94 user_access_end(); 72323cc0a0d77f Peter Oskolkov 2021-09-17 95 72323cc0a0d77f Peter Oskolkov 2021-09-17 96 if (!ret) 72323cc0a0d77f Peter Oskolkov 2021-09-17 97 ret = *old == __old ? 0 : -EAGAIN; 72323cc0a0d77f Peter Oskolkov 2021-09-17 98 72323cc0a0d77f Peter Oskolkov 2021-09-17 99 pagefault_enable(); 72323cc0a0d77f Peter Oskolkov 2021-09-17 100 return ret; 72323cc0a0d77f Peter Oskolkov 2021-09-17 101 } 72323cc0a0d77f Peter Oskolkov 2021-09-17 102 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org