tree: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git master head: 7b18c2d1930b99fc2acd4b9499a55f51df2a6678 commit: dde56e52f55a3bed98d1b02d83ab4376c7e152b4 [387/476] x86/mm/tlb: Flush remote and local TLBs concurrently config: x86_64-randconfig-a003-20210215 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project c9439ca36342fb6013187d0a69aef92736951476) 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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?... git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git git fetch --no-tags peterz-queue master git checkout dde56e52f55a3bed98d1b02d83ab4376c7e152b4 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): flush_tlb_func(info); ^~~~ arch/x86/mm/tlb.c:1158:29: note: initialize the variable 'info' to silence this warning struct flush_tlb_info *info; ^ = NULL 1 warning generated. vim +/info +1172 arch/x86/mm/tlb.c 2faf153bb7346b Thomas Gleixner 2020-04-21 1155 3db6d5a5ecaf0a Nadav Amit 2019-04-25 1156 void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch) 3db6d5a5ecaf0a Nadav Amit 2019-04-25 1157 { edd07111673cdd Nadav Amit 2021-02-09 1158 struct flush_tlb_info *info; edd07111673cdd Nadav Amit 2021-02-09 1159 e73ad5ff2f76da Andy Lutomirski 2017-05-22 1160 int cpu = get_cpu(); e73ad5ff2f76da Andy Lutomirski 2017-05-22 1161 dde56e52f55a3b Nadav Amit 2021-02-09 1162 /* dde56e52f55a3b Nadav Amit 2021-02-09 1163 * flush_tlb_multi() is not optimized for the common case in which only dde56e52f55a3b Nadav Amit 2021-02-09 1164 * a local TLB flush is needed. Optimize this use-case by calling dde56e52f55a3b Nadav Amit 2021-02-09 1165 * flush_tlb_func_local() directly in this case. dde56e52f55a3b Nadav Amit 2021-02-09 1166 */ dde56e52f55a3b Nadav Amit 2021-02-09 1167 if (cpumask_any_but(&batch->cpumask, cpu) < nr_cpu_ids) { dde56e52f55a3b Nadav Amit 2021-02-09 1168 flush_tlb_multi(&batch->cpumask, info); dde56e52f55a3b Nadav Amit 2021-02-09 1169 } else if (cpumask_test_cpu(cpu, &batch->cpumask)) { 3db6d5a5ecaf0a Nadav Amit 2019-04-25 1170 lockdep_assert_irqs_enabled(); bc0d5a89fbe3c8 Andy Lutomirski 2017-06-29 1171 local_irq_disable(); edd07111673cdd Nadav Amit 2021-02-09 @1172 flush_tlb_func(info); bc0d5a89fbe3c8 Andy Lutomirski 2017-06-29 1173 local_irq_enable(); bc0d5a89fbe3c8 Andy Lutomirski 2017-06-29 1174 } bc0d5a89fbe3c8 Andy Lutomirski 2017-06-29 1175 e73ad5ff2f76da Andy Lutomirski 2017-05-22 1176 cpumask_clear(&batch->cpumask); e73ad5ff2f76da Andy Lutomirski 2017-05-22 1177 edd07111673cdd Nadav Amit 2021-02-09 1178 put_flush_tlb_info(); e73ad5ff2f76da Andy Lutomirski 2017-05-22 1179 put_cpu(); e73ad5ff2f76da Andy Lutomirski 2017-05-22 1180 } e73ad5ff2f76da Andy Lutomirski 2017-05-22 1181 :::::: The code at line 1172 was first introduced by commit :::::: edd07111673cddd0689de853c9869fdba0b41bfb x86/mm/tlb: Unify flush_tlb_func_local() and flush_tlb_func_remote() :::::: TO: Nadav Amit <namit(a)vmware.com&gt; :::::: CC: Peter Zijlstra <peterz(a)infradead.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org