[PATCH 5.5 148/257] KVM: x86: Gracefully handle __vmalloc() failure during VM allocation

From: Greg Kroah-Hartman
Date: Thu Apr 16 2020 - 11:40:24 EST


From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>

commit d18b2f43b9147c8005ae0844fb445d8cc6a87e31 upstream.

Check the result of __vmalloc() to avoid dereferencing a NULL pointer in
the event that allocation failres.

Fixes: d1e5b0e98ea27 ("kvm: Make VM ioctl do valloc for some archs")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/kvm/svm.c | 4 ++++
arch/x86/kvm/vmx/vmx.c | 4 ++++
2 files changed, 8 insertions(+)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1930,6 +1930,10 @@ static struct kvm *svm_vm_alloc(void)
struct kvm_svm *kvm_svm = __vmalloc(sizeof(struct kvm_svm),
GFP_KERNEL_ACCOUNT | __GFP_ZERO,
PAGE_KERNEL);
+
+ if (!kvm_svm)
+ return NULL;
+
return &kvm_svm->kvm;
}

--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6633,6 +6633,10 @@ static struct kvm *vmx_vm_alloc(void)
struct kvm_vmx *kvm_vmx = __vmalloc(sizeof(struct kvm_vmx),
GFP_KERNEL_ACCOUNT | __GFP_ZERO,
PAGE_KERNEL);
+
+ if (!kvm_vmx)
+ return NULL;
+
return &kvm_vmx->kvm;
}