[PATCH] Don't destroy vcpu in case vcpu_setup fails

[PATCH] Don't destroy vcpu in case vcpu_setup fails

[Glauber Costa]

One of vcpu_setup responsibilities is to do mmu initialization.
However, in case we fail in kvm_arch_vcpu_reset, before we get the
chance to init mmu. OTOH, vcpu_destroy will attempt to destroy mmu,
triggering a bug. Keeping track of whether or not mmu is initialized
would unnecessarily complicate things. Rather, we just make return,
making sure any needed uninitialization is done before we return, in
case we fail.

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 virt/kvm/kvm_main.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f42d5c2..644567f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1089,12 +1089,11 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
 
 	r = kvm_arch_vcpu_setup(vcpu);
 	if (r)
-		goto vcpu_destroy;
+		return r;
 
 	mutex_lock(&kvm->lock);
 	if (kvm->vcpus[n]) {
 		r = -EEXIST;
-		mutex_unlock(&kvm->lock);
 		goto vcpu_destroy;
 	}
 	kvm->vcpus[n] = vcpu;
@@ -1110,8 +1109,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
 unlink:
 	mutex_lock(&kvm->lock);
 	kvm->vcpus[n] = NULL;
-	mutex_unlock(&kvm->lock);
 vcpu_destroy:
+	mutex_unlock(&kvm->lock);
 	kvm_arch_vcpu_destroy(vcpu);
 	return r;
 }
-- 
1.5.5.1

Re: [PATCH] Don't destroy vcpu in case vcpu_setup fails

[Avi Kivity]

Glauber Costa wrote:
> One of vcpu_setup responsibilities is to do mmu initialization.
> However, in case we fail in kvm_arch_vcpu_reset, before we get the
> chance to init mmu. OTOH, vcpu_destroy will attempt to destroy mmu,
> triggering a bug. Keeping track of whether or not mmu is initialized
> would unnecessarily complicate things. Rather, we just make return,
> making sure any needed uninitialization is done before we return, in
> case we fail.
>   

Applied, thanks.

-- 
error compiling committee.c: too many arguments to function