Messages in this thread | | | Subject | Re: [PATCH] KVM: fix spin_lock_init order on x86 | From | Eric Dumazet <> | Date | Mon, 21 Mar 2016 07:47:15 -0700 |
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On Mon, 2016-03-21 at 10:24 +0100, Paolo Bonzini wrote: > kvm_arch_init_vm is now using mmu_lock, causing lockdep to > complain: ... > > Reported-by: Borislav Petkov <bp@alien8.de> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > 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);
current->mm->mm_count is incremented here.
> + 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;
But out_err_no_disable wont decrement it in case of an error.
This is not clear to me where the cleanup is done ?
> @@ -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;
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