tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git x86/fpu-kvm head: e16d6eec3c9e60abfb29d0d77f08411d326142dd commit: 8a4ae8c80ec211646b5824b7c89d64cf7d286625 [1/6] x86/fpu: Extend fpu_xstate_prctl() with guest permissions config: x86_64-randconfig-r035-20211213 (https://download.01.org/0day-ci/archive/20211214/202112141631.KodrezTK-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project b6a2ddb6c8ac29412b1361810972e15221fa021c) 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 8a4ae8c80ec211646b5824b7c89d64cf7d286625 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/kernel/fpu/ 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 >>): if (!guest) { ^~~~~~ arch/x86/kernel/fpu/xstate.c:1637:9: note: uninitialized use occurs here return ret; ^~~ arch/x86/kernel/fpu/xstate.c:1625:2: note: remove the 'if' if its condition is always true if (!guest) { ^~~~~~~~~~~~ arch/x86/kernel/fpu/xstate.c:1611:9: note: initialize the variable 'ret' to silence this warning int ret; ^ = 0 1 warning generated. vim +1625 arch/x86/kernel/fpu/xstate.c 1597 1598 static int __xstate_request_perm(u64 permitted, u64 requested, bool guest) 1599 { 1600 /* 1601 * This deliberately does not exclude !XSAVES as we still might 1602 * decide to optionally context switch XCR0 or talk the silicon 1603 * vendors into extending XFD for the pre AMX states, especially 1604 * AVX512. 1605 */ 1606 bool compacted = cpu_feature_enabled(X86_FEATURE_XSAVES); 1607 struct fpu *fpu = &current->group_leader->thread.fpu; 1608 struct fpu_state_perm *perm; 1609 unsigned int ksize, usize; 1610 u64 mask; 1611 int ret; 1612 1613 /* Check whether fully enabled */ 1614 if ((permitted & requested) == requested) 1615 return 0; 1616 1617 /* Calculate the resulting kernel state size */ 1618 mask = permitted | requested; 1619 ksize = xstate_calculate_size(mask, compacted); 1620 1621 /* Calculate the resulting user state size */ 1622 mask &= XFEATURE_MASK_USER_SUPPORTED; 1623 usize = xstate_calculate_size(mask, false); 1624 1626 ret = validate_sigaltstack(usize); 1627 if (ret) 1628 return ret; 1629 } 1630 1631 perm = guest ? &fpu->guest_perm : &fpu->perm; 1632 /* Pairs with the READ_ONCE() in xstate_get_group_perm() */ 1633 WRITE_ONCE(perm->__state_perm, requested); 1634 /* Protected by sighand lock */ 1635 perm->__state_size = ksize; 1636 perm->__user_state_size = usize; 1637 return ret; 1638 } 1639 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org