KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices

We were not holding the kvm->slots_lock as required when calling
kvm_io_bus_unregister_dev() as required.

This only affects the error path, but still, let's do our due
diligence.

Reported by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index 9b0f6810e7a87405d2de47c33ec3ebca51de3bab..201d5e2e973dd4504c1f41747b2f07bb797ade11 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -614,15 +614,16 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
        mutex_lock(&kvm->slots_lock);
        ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, sgi_base,
                                      SZ_64K, &sgi_dev->dev);
-       mutex_unlock(&kvm->slots_lock);
        if (ret) {
                kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS,
                                          &rd_dev->dev);
-               return ret;
+               goto out;
        }
 
        vgic->vgic_redist_free_offset += 2 * SZ_64K;
-       return 0;
+out:
+       mutex_unlock(&kvm->slots_lock);
+       return ret;
 }
 
 static void vgic_unregister_redist_iodev(struct kvm_vcpu *vcpu)
@@ -647,10 +648,12 @@ static int vgic_register_all_redist_iodevs(struct kvm *kvm)
 
        if (ret) {
                /* The current c failed, so we start with the previous one. */
+               mutex_lock(&kvm->slots_lock);
                for (c--; c >= 0; c--) {
                        vcpu = kvm_get_vcpu(kvm, c);
                        vgic_unregister_redist_iodev(vcpu);
                }
+               mutex_unlock(&kvm->slots_lock);
        }
 
        return ret;