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authorMike Waychison <mikew@google.com>2011-06-03 13:04:53 -0700
committerAvi Kivity <avi@redhat.com>2011-06-06 11:27:52 +0300
commit74b5c5bfff429f464c38dd49af41d75cf0e7dc26 (patch)
treef191213a9807e88ca24c2aaf123734892fe9e792 /virt
parent221192bdff2583834984639121595fc9296120d3 (diff)
KVM: Initialize kvm before registering the mmu notifier
It doesn't make sense to ever see a half-initialized kvm structure on mmu notifier callbacks. Previously, 85722cda changed the ordering to ensure that the mmu_lock was initialized before mmu notifier registration, but there is still a race where the mmu notifier could come in and try accessing other portions of struct kvm before they are intialized. Solve this by moving the mmu notifier registration to occur after the structure is completely initialized. Google-Bug-Id: 452199 Signed-off-by: Mike Waychison <mikew@google.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 383f492a660..96ebc067941 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -467,12 +467,8 @@ static struct kvm *kvm_create_vm(void)
if (!kvm->buses[i])
goto out_err;
}
- spin_lock_init(&kvm->mmu_lock);
-
- r = kvm_init_mmu_notifier(kvm);
- if (r)
- goto out_err;
+ spin_lock_init(&kvm->mmu_lock);
kvm->mm = current->mm;
atomic_inc(&kvm->mm->mm_count);
kvm_eventfd_init(kvm);
@@ -480,6 +476,11 @@ static struct kvm *kvm_create_vm(void)
mutex_init(&kvm->irq_lock);
mutex_init(&kvm->slots_lock);
atomic_set(&kvm->users_count, 1);
+
+ r = kvm_init_mmu_notifier(kvm);
+ if (r)
+ goto out_err;
+
raw_spin_lock(&kvm_lock);
list_add(&kvm->vm_list, &vm_list);
raw_spin_unlock(&kvm_lock);