Hi Sean, I love your patch! Perhaps something to improve: [auto build test WARNING on kvm/queue] [also build test WARNING on next-20211029] [cannot apply to v5.15-rc7] [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/Sean-Christopherson/KVM-x86-Shove-vp_bitmap-handling-down-into-sparse_set_to_vcpu_mask/20211029-053606 base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue config: x86_64-randconfig-a015-20211031 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 82ed106567063ea269c6d5669278b733e173a42f) 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://github.com/0day-ci/linux/commit/1a2811bcda8f6cc49c4458744e96bdbabc3a38b0 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Sean-Christopherson/KVM-x86-Shove-vp_bitmap-handling-down-into-sparse_set_to_vcpu_mask/20211029-053606 git checkout 1a2811bcda8f6cc49c4458744e96bdbabc3a38b0 # 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@xxxxxxxxx> All warnings (new ones prefixed by >>): >> arch/x86/kvm/hyperv.c:1727:6: warning: variable 'bitmap' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (likely(!has_mismatch)) ^~~~~~~~~~~~~~~~~~~~~ include/linux/compiler.h:45:21: note: expanded from macro 'likely' # define likely(x) (__branch_check__(x, 1, __builtin_constant_p(x))) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/x86/kvm/hyperv.c:1730:9: note: uninitialized use occurs here memset(bitmap, 0, sizeof(vp_bitmap)); ^~~~~~ arch/x86/kvm/hyperv.c:1727:2: note: remove the 'if' if its condition is always true if (likely(!has_mismatch)) ^~~~~~~~~~~~~~~~~~~~~~~~~~ arch/x86/kvm/hyperv.c:1721:13: note: initialize the variable 'bitmap' to silence this warning u64 *bitmap; ^ = NULL 1 warning generated. vim +1727 arch/x86/kvm/hyperv.c 1712 1713 static void sparse_set_to_vcpu_mask(struct kvm *kvm, u64 *sparse_banks, 1714 u64 valid_bank_mask, unsigned long *vcpu_mask) 1715 { 1716 struct kvm_hv *hv = to_kvm_hv(kvm); 1717 bool has_mismatch = atomic_read(&hv->num_mismatched_vp_indexes); 1718 u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; 1719 struct kvm_vcpu *vcpu; 1720 int i, bank, sbank = 0; 1721 u64 *bitmap; 1722 1723 BUILD_BUG_ON(sizeof(vp_bitmap) > 1724 sizeof(*vcpu_mask) * BITS_TO_LONGS(KVM_MAX_VCPUS)); 1725 1726 /* If vp_index == vcpu_idx for all vCPUs, fill vcpu_mask directly. */ > 1727 if (likely(!has_mismatch)) 1728 bitmap = (u64 *)vcpu_mask; 1729 1730 memset(bitmap, 0, sizeof(vp_bitmap)); 1731 for_each_set_bit(bank, (unsigned long *)&valid_bank_mask, 1732 KVM_HV_MAX_SPARSE_VCPU_SET_BITS) 1733 bitmap[bank] = sparse_banks[sbank++]; 1734 1735 if (likely(!has_mismatch)) 1736 return; 1737 1738 bitmap_zero(vcpu_mask, KVM_MAX_VCPUS); 1739 kvm_for_each_vcpu(i, vcpu, kvm) { 1740 if (test_bit(kvm_hv_get_vpindex(vcpu), (unsigned long *)vp_bitmap)) 1741 __set_bit(i, vcpu_mask); 1742 } 1743 } 1744 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
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