diff options
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 27b97e546980..13ac4d0f9794 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9715,9 +9715,9 @@ void kvm_arch_sync_events(struct kvm *kvm) int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) { int i, r; - unsigned long hva; + unsigned long hva, uninitialized_var(old_npages); struct kvm_memslots *slots = kvm_memslots(kvm); - struct kvm_memory_slot *slot, old; + struct kvm_memory_slot *slot; /* Called with kvm->slots_lock held. */ if (WARN_ON(id >= KVM_MEM_SLOTS_NUM)) @@ -9725,7 +9725,7 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) slot = id_to_memslot(slots, id); if (size) { - if (slot->npages) + if (slot && slot->npages) return -EEXIST; /* @@ -9737,13 +9737,14 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) if (IS_ERR((void *)hva)) return PTR_ERR((void *)hva); } else { - if (!slot->npages) + if (!slot || !slot->npages) return 0; - hva = 0; + /* Stuff a non-canonical value to catch use-after-delete. */ + hva = 0xdeadull << 48; + old_npages = slot->npages; } - old = *slot; for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { struct kvm_userspace_memory_region m; @@ -9758,7 +9759,7 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) } if (!size) - vm_munmap(old.userspace_addr, old.npages * PAGE_SIZE); + vm_munmap(hva, old_npages * PAGE_SIZE); return 0; } |