[PATCH] KVM: fix spin_lock_init order on x86

From: Paolo Bonzini
Date: Mon Mar 21 2016 - 05:25:30 EST


kvm_arch_init_vm is now using mmu_lock, causing lockdep to
complain:

[ 284.440294] INFO: trying to register non-static key.
[ 284.445259] the code is fine but needs lockdep annotation.
[ 284.450736] turning off the locking correctness validator.
...
[ 284.528318] [<ffffffff810aecc3>] lock_acquire+0xd3/0x240
[ 284.533733] [<ffffffffa0305aa0>] ? kvm_page_track_register_notifier+0x20/0x60 [kvm]
[ 284.541467] [<ffffffff81715581>] _raw_spin_lock+0x41/0x80
[ 284.546960] [<ffffffffa0305aa0>] ? kvm_page_track_register_notifier+0x20/0x60 [kvm]
[ 284.554707] [<ffffffffa0305aa0>] kvm_page_track_register_notifier+0x20/0x60 [kvm]
[ 284.562281] [<ffffffffa02ece70>] kvm_mmu_init_vm+0x20/0x30 [kvm]
[ 284.568381] [<ffffffffa02dbf7a>] kvm_arch_init_vm+0x1ea/0x200 [kvm]
[ 284.574740] [<ffffffffa02bff3f>] kvm_dev_ioctl+0xbf/0x4d0 [kvm]

Reported-by: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
virt/kvm/kvm_main.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7ba1d10ffed2..cb45b86a1c48 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -536,6 +536,16 @@ static struct kvm *kvm_create_vm(unsigned long type)
if (!kvm)
return ERR_PTR(-ENOMEM);

+ spin_lock_init(&kvm->mmu_lock);
+ kvm->mm = current->mm;
+ atomic_inc(&kvm->mm->mm_count);
+ kvm_eventfd_init(kvm);
+ mutex_init(&kvm->lock);
+ mutex_init(&kvm->irq_lock);
+ mutex_init(&kvm->slots_lock);
+ atomic_set(&kvm->users_count, 1);
+ INIT_LIST_HEAD(&kvm->devices);
+
r = kvm_arch_init_vm(kvm, type);
if (r)
goto out_err_no_disable;
@@ -568,16 +578,6 @@ static struct kvm *kvm_create_vm(unsigned long type)
goto out_err;
}

- spin_lock_init(&kvm->mmu_lock);
- kvm->mm = current->mm;
- atomic_inc(&kvm->mm->mm_count);
- kvm_eventfd_init(kvm);
- mutex_init(&kvm->lock);
- mutex_init(&kvm->irq_lock);
- mutex_init(&kvm->slots_lock);
- atomic_set(&kvm->users_count, 1);
- INIT_LIST_HEAD(&kvm->devices);
-
r = kvm_init_mmu_notifier(kvm);
if (r)
goto out_err;
--
1.8.3.1