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[v2,1/3] kvm: arm/arm64: Take mmap_sem in stage2_unmap_vm

Message ID 1489688451-17520-2-git-send-email-suzuki.poulose@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Suzuki K Poulose March 16, 2017, 6:20 p.m. UTC 
From: Marc Zyngier <marc.zyngier@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@vger.kernel.org # v3.19+
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arch/arm/kvm/mmu.c | 2 ++
 1 file changed, 2 insertions(+)
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Patch

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(&current->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(&current->mm->mmap_sem);
 	srcu_read_unlock(&kvm->srcu, idx);
 }