[PATCH 1/3] kvm: arm/arm64: Take mmap_sem in stage2_unmap_vm
Suzuki K Poulose
suzuki.poulose at arm.com
Tue Mar 14 07:52:32 PDT 2017
From: Marc Zyngier <marc.zyngier at arm.com>
We don't hold the mmap_sem while searching for the VMAs when
we try to unmap each memslot for a VM. Fix this properly to
avoid unexpected results.
Fixes: commit 957db105c997 ("arm/arm64: KVM: Introduce stage2_unmap_vm")
Cc: stable at vger.kernel.org # v3.19+
Cc: Christoffer Dall <christoffer.dall at linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
---
arch/arm/kvm/mmu.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 962616f..f2e2e0c 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -803,6 +803,7 @@ void stage2_unmap_vm(struct kvm *kvm)
int idx;
idx = srcu_read_lock(&kvm->srcu);
+ down_read(¤t->mm->mmap_sem);
spin_lock(&kvm->mmu_lock);
slots = kvm_memslots(kvm);
@@ -810,6 +811,7 @@ void stage2_unmap_vm(struct kvm *kvm)
stage2_unmap_memslot(kvm, memslot);
spin_unlock(&kvm->mmu_lock);
+ up_read(¤t->mm->mmap_sem);
srcu_read_unlock(&kvm->srcu, idx);
}
--
2.7.4
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