KVM: MMU: make __kvm_mmu_free_some_pages handle empty list

commit 3b80fffe2b31fb716d3ebe729c54464ee7856723 upstream.

First check if the list is empty before attempting to look at list
entries.

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 0ef5bb2b4043af68c70ce46dbe484e3a887f8a21..a5cdb35af510e3dc2cc9eb9c8a4f10991738f445 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2633,7 +2633,8 @@ EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
 
 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
 {
-       while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
+       while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES &&
+              !list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
                struct kvm_mmu_page *sp;
 
                sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,