From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Wed, 17 Sep 2014 14:56:17 -0700 Subject: [PATCH 2/6] arm/arm64: KVM: fix potential NULL dereference in user_mem_abort() In-Reply-To: <1410990981-665-1-git-send-email-ard.biesheuvel@linaro.org> References: <1410990981-665-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <1410990981-665-3-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Handle the potential NULL return value of find_vma_intersection() before dereferencing it. Signed-off-by: Ard Biesheuvel --- arch/arm/kvm/mmu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 152e0f896e63..c093e95ff7ef 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -776,7 +776,11 @@ 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 (is_vm_hugetlb_page(vma)) { + if (unlikely(!vma)) { + kvm_err("Failed to find VMA for hva 0x%lx\n", hva); + up_read(¤t->mm->mmap_sem); + return -EFAULT; + } else if (is_vm_hugetlb_page(vma)) { hugetlb = true; gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT; } else { -- 1.8.3.2