KVM: VMX: Ensure that vmx_create_vcpu always returns proper error

In case certain allocations fail, vmx_create_vcpu may return 0 as error
instead of a negative value encoded via ERR_PTR. This causes a NULL
pointer dereferencing later on in kvm_vm_ioctl_vcpu_create.

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index aabe3334d064..af5206983154 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4251,8 +4251,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
                 goto free_vcpu;
 
         vmx->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
+        err = -ENOMEM;
         if (!vmx->guest_msrs) {
-                err = -ENOMEM;
                 goto uninit_vcpu;
         }
 
@@ -4271,7 +4271,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
         if (err)
                 goto free_vmcs;
         if (vm_need_virtualize_apic_accesses(kvm))
-                if (alloc_apic_access_page(kvm) != 0)
+                err = alloc_apic_access_page(kvm);
+                if (err)
                         goto free_vmcs;
 
         if (enable_ept) {