KVM: Fix unlikely kvm_create vs decache_vcpus_on_cpu race
We add the kvm to the vm_list before initializing the vcpu mutexes,
which can be mutex_trylock()'ed by decache_vcpus_on_cpu().
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index a0a3fdd..46efbe7 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -297,9 +297,6 @@
kvm_io_bus_init(&kvm->pio_bus);
spin_lock_init(&kvm->lock);
INIT_LIST_HEAD(&kvm->active_mmu_pages);
- spin_lock(&kvm_lock);
- list_add(&kvm->vm_list, &vm_list);
- spin_unlock(&kvm_lock);
kvm_io_bus_init(&kvm->mmio_bus);
for (i = 0; i < KVM_MAX_VCPUS; ++i) {
struct kvm_vcpu *vcpu = &kvm->vcpus[i];
@@ -309,6 +306,9 @@
vcpu->kvm = kvm;
vcpu->mmu.root_hpa = INVALID_PAGE;
}
+ spin_lock(&kvm_lock);
+ list_add(&kvm->vm_list, &vm_list);
+ spin_unlock(&kvm_lock);
return kvm;
}