Hi Nicholas, [FYI, it's a private test report for your RFC patch.] [auto build test ERROR on sparc/master] [also build test ERROR on powerpc/next sparc-next/master v5.9-rc1 next-20200817] [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/Nicholas-Piggin/sparc64-remove-m... base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc.git master config: sparc-allyesconfig (attached as .config) compiler: sparc64-linux-gcc (GCC) 9.3.0 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 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sparc 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 >>): arch/sparc/kernel/smp_64.c: In function 'smp_flush_tlb_mm': 1053 | int cpu = get_cpu(); | ^~~ arch/sparc/kernel/smp_64.c: In function 'smp_flush_tlb_pending': arch/sparc/kernel/smp_64.c:1081:6: error: unused variable 'cpu' [-Werror=unused-variable] 1081 | int cpu = get_cpu(); | ^~~ arch/sparc/kernel/smp_64.c: In function 'smp_flush_tlb_page': arch/sparc/kernel/smp_64.c:1098:6: error: unused variable 'cpu' [-Werror=unused-variable] 1098 | int cpu = get_cpu(); | ^~~ cc1: all warnings being treated as errors # https://github.com/0day-ci/linux/commit/9af8f1e046bb13612593bd8fcd3f98347... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Nicholas-Piggin/sparc64-remove-mm_cpumask-clearing-to-fix-kthread_use_mm-race/20200818-113600 git checkout 9af8f1e046bb13612593bd8fcd3f98347223203b vim +/cpu +1053 arch/sparc/kernel/smp_64.c 916ca14aaf12a71 arch/sparc/kernel/smp_64.c David S. Miller 2012-10-16 1035 ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1036 /* We know that the window frames of the user have been flushed ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1037 * to the stack before we get here because all callers of us ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1038 * are flush_tlb_*() routines, and these run after flush_cache_*() ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1039 * which performs the flushw. ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1040 * 9af8f1e046bb136 arch/sparc/kernel/smp_64.c Nicholas Piggin 2020-08-18 1041 * mm->cpu_vm_mask is a bit mask of which cpus an address ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1042 * space has (potentially) executed on, this is the heuristic 9af8f1e046bb136 arch/sparc/kernel/smp_64.c Nicholas Piggin 2020-08-18 1043 * we use to limit cross calls. ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1044 */ ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1045 62dbec78be652c2 arch/sparc64/kernel/smp.c David S. Miller 2005-11-07 1046 /* This currently is only used by the hugetlb arch pre-fault 62dbec78be652c2 arch/sparc64/kernel/smp.c David S. Miller 2005-11-07 1047 * hook on UltraSPARC-III+ and later when changing the pagesize 62dbec78be652c2 arch/sparc64/kernel/smp.c David S. Miller 2005-11-07 1048 * bits of the context register for an address space. 62dbec78be652c2 arch/sparc64/kernel/smp.c David S. Miller 2005-11-07 1049 */ 62dbec78be652c2 arch/sparc64/kernel/smp.c David S. Miller 2005-11-07 1050 void smp_flush_tlb_mm(struct mm_struct *mm) ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1051 { ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1052 u32 ctx = CTX_HWBITS(mm->context); ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 @1053 int cpu = get_cpu(); ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1054 ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1055 smp_cross_call_masked(&xcall_flush_tlb_mm, ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1056 ctx, 0, 0, 81f1adf01224f5c arch/sparc/kernel/smp_64.c Rusty Russell 2009-03-16 1057 mm_cpumask(mm)); ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1058 ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1059 __flush_tlb_mm(ctx, SECONDARY_CONTEXT); ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1060 ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1061 put_cpu(); ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1062 } ^1da177e4c3f415 arch/sparc64/kernel/smp.c Linus Torvalds 2005-04-16 1063 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org