From 883bc09b140752f699610f6582ffe08fd26ee71e Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 16 Mar 2017 18:20:50 +0000 Subject: [PATCH] arm/arm64: KVM: Take mmap_sem in kvm_arch_prepare_memory_region commit 72f310481a08db821b614e7b5d00febcc9064b36 upstream. We don't hold the mmap_sem while searching for VMAs (via find_vma), in kvm_arch_prepare_memory_region, which can end up in expected failures. Fixes: commit 8eef91239e57 ("arm/arm64: KVM: map MMIO regions at creation time") Cc: Ard Biesheuvel Cc: Eric Auger Reviewed-by: Christoffer Dall [ Handle dirty page logging failure case ] Signed-off-by: Suzuki K Poulose Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman --- arch/arm/kvm/mmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index feda3ff185e9..9fb14a37263b 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -1407,6 +1407,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, (KVM_PHYS_SIZE >> PAGE_SHIFT)) return -EFAULT; + down_read(¤t->mm->mmap_sem); /* * A memory region could potentially cover multiple VMAs, and any holes * between them, so iterate over all of them to find out if we can map @@ -1464,6 +1465,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, else stage2_flush_memslot(kvm, memslot); spin_unlock(&kvm->mmu_lock); + + up_read(¤t->mm->mmap_sem); return ret; }