On 24/10/19 04:59, Junaid Shahid wrote:
> AFAICT the kvm->users_count is already 0 before kvm_arch_destroy_vm()
> is called from kvm_destroy_vm() in the normal case.
Yes:
if (refcount_dec_and_test(&kvm->users_count))
kvm_destroy_vm(kvm);
where
| int atomic_inc_and_test(atomic_t *v);
| int atomic_dec_and_test(atomic_t *v);
|
| These two routines increment and decrement by 1, respectively, the
| given atomic counter. They return a boolean indicating whether the
| resulting counter value was zero or not.
> So there really
> shouldn't be any arch that does a kvm_put_kvm() inside
> kvm_arch_destroy_vm(). I think it might be better to keep the
> kvm_arch_destroy_vm() call after the refcount_set() to be consistent
> with the normal path.
I agree, so I am applying Jim's patch. If anything, we may want to WARN
if the refcount is not 1 before the refcount_set.
Paolo
