From 37b544087ef3f65ca68465ba39291a07195dac26 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 17 Sep 2014 14:56:17 -0700 Subject: [PATCH] arm/arm64: KVM: fix potential NULL dereference in user_mem_abort() Handle the potential NULL return value of find_vma_intersection() before dereferencing it. Acked-by: Marc Zyngier Signed-off-by: Ard Biesheuvel Signed-off-by: Christoffer Dall --- arch/arm/kvm/mmu.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 8f0c7a4c49fc..bb2e110e77c0 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -776,6 +776,12 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, /* Let's check if we will get back a huge page backed by hugetlbfs */ down_read(¤t->mm->mmap_sem); vma = find_vma_intersection(current->mm, hva, hva + 1); + if (unlikely(!vma)) { + kvm_err("Failed to find VMA for hva 0x%lx\n", hva); + up_read(¤t->mm->mmap_sem); + return -EFAULT; + } + if (is_vm_hugetlb_page(vma)) { hugetlb = true; gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT; -- 2.39.2