tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git x86/fpu-kvm head: dc3cd5721cdb0d3116a2feb84755427d1522477a commit: dc3cd5721cdb0d3116a2feb84755427d1522477a [88/88] x86/fpu: Add reallocation mechanims for KVM config: x86_64-randconfig-r031-20211017 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 746dd6a700931988dd9021d3d04718f1929885a5) 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 # https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git/commit/?id... git remote add tglx-devel https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git git fetch --no-tags tglx-devel x86/fpu-kvm git checkout dc3cd5721cdb0d3116a2feb84755427d1522477a # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 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 >>): int ret; ^ 1 warning generated. vim +/ret +281 arch/x86/kernel/fpu/core.c 275 276 int fpu_swap_kvm_fpstate(struct fpu_guest *guest_fpu, bool enter_guest, 277 u64 restore_mask) 278 { 279 struct fpstate *guest_fps, *cur_fps; 280 struct fpu *fpu = &current->thread.fpu; 282 283 if (unlikely(guest_fpu->realloc_request)) 284 ret = fpu_guest_realloc_fpstate(guest_fpu, enter_guest); 285 286 guest_fps = guest_fpu->fpstate; 287 cur_fps = fpu->fpstate; 288 289 fpregs_lock(); 290 if (!cur_fps->is_confidential && !test_thread_flag(TIF_NEED_FPU_LOAD)) 291 save_fpregs_to_fpstate(fpu); 292 293 /* Swap fpstate */ 294 if (enter_guest) { 295 fpu->__task_fpstate = cur_fps; 296 fpu->fpstate = guest_fps; 297 guest_fps->in_use = true; 298 } else { 299 guest_fps->in_use = false; 300 fpu->fpstate = fpu->__task_fpstate; 301 fpu->__task_fpstate = NULL; 302 } 303 304 cur_fps = fpu->fpstate; 305 306 if (!cur_fps->is_confidential) { 307 restore_mask &= XFEATURE_MASK_FPSTATE; 308 /* Includes XFD update */ 309 restore_fpregs_from_fpstate(cur_fps, restore_mask); 310 } else { 311 /* 312 * XSTATE is restored by firmware from encrypted 313 * memory. Make sure XFD state is correct while 314 * running with guest fpstate 315 */ 316 xfd_update_state(cur_fps); 317 } 318 319 fpregs_mark_activate(); 320 fpregs_unlock(); 321 return 0; 322 } 323 EXPORT_SYMBOL_GPL(fpu_swap_kvm_fpstate); 324 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org