From 7465894e90e5a47e0e52aa5f1f708653fc40020f Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Thu, 30 Nov 2017 17:00:30 +0000
Subject: KVM: arm/arm64: Fix spinlock acquisition in vgic_set_owner
vgic_set_owner acquires the irq lock without disabling interrupts,
resulting in a lockdep splat (an interrupt could fire and result
in the same lock being taken if the same virtual irq is to be
injected).
In practice, it is almost impossible to trigger this bug, but
better safe than sorry. Convert the lock acquisition to a
spin_lock_irqsave() and keep lockdep happy.
Reported-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
virt/kvm/arm/vgic/vgic.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
(limited to 'virt')
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 786cce7bd2ec..ecb8e25f5fe5 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -492,6 +492,7 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner)
{
struct vgic_irq *irq;
+ unsigned long flags;
int ret = 0;
if (!vgic_initialized(vcpu->kvm))
@@ -502,12 +503,12 @@ int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner)
return -EINVAL;
irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
- spin_lock(&irq->irq_lock);
+ spin_lock_irqsave(&irq->irq_lock, flags);
if (irq->owner && irq->owner != owner)
ret = -EEXIST;
else
irq->owner = owner;
- spin_unlock(&irq->irq_lock);
+ spin_unlock_irqrestore(&irq->irq_lock, flags);
return ret;
}
--
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