tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/pti head: 767d46ab566dd489733666efe48732d523c8c332 commit: b6724f118d44606fddde391ba7527526b3cad211 [4/5] prctl: Hook L1D flushing in via prctl config: i386-randconfig-r026-20210115 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=b6... git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git git fetch --no-tags tip x86/pti git checkout b6724f118d44606fddde391ba7527526b3cad211 # save the attached .config to linux build tree make W=1 ARCH=i386 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 >>): arch/x86/mm/tlb.c: In function 'enable_l1d_flush_for_task': 319 | int cpu, ret = 0, i; | ^~~ vim +/cpu +319 arch/x86/mm/tlb.c 316 317 int enable_l1d_flush_for_task(struct task_struct *tsk) 318 { 320 321 /* 322 * Do not enable L1D_FLUSH_OUT if 323 * b. The CPU is not affected by the L1TF bug 324 * c. The CPU does not have L1D FLUSH feature support 325 * c. The task's affinity is on cores with SMT on. 326 */ 327 328 if (!boot_cpu_has_bug(X86_BUG_L1TF) || 329 !static_cpu_has(X86_FEATURE_FLUSH_L1D)) 330 return -EINVAL; 331 332 cpu = get_cpu(); 333 334 for_each_cpu(i, &tsk->cpus_mask) { 335 if (cpu_data(i).smt_active == true) { 336 put_cpu(); 337 return -EINVAL; 338 } 339 } 340 341 set_ti_thread_flag(&tsk->thread_info, TIF_SPEC_L1D_FLUSH); 342 put_cpu(); 343 return ret; 344 } 345 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org