Re: [PATCH 2/2] KVM: selftests: Fix FD double-close in kvm_vm_release()

[Ackerley Tng]

Fuad Tabba <tabba@xxxxxxxxxx> writes:

I agree that perhaps in this case manually setting up the memslot after
mmap()-ing anonymous memory is better since it's more explicit about
what is being tested.

> kvm_vm_release() closes vmp->fd and vmp->kvm_fd unconditionally, and
> kvm_vm_free() calls kvm_vm_release() at teardown.  A test that calls
> kvm_vm_release() and then kvm_vm_free() without a
> vm_recreate_with_one_vcpu() in between double-closes both FDs.  Since
> kvm_close() asserts on close() failure, the second close trips
> TEST_ASSERT and aborts the test, or, if the FD was recycled, silently
> closes an unrelated file.
>

Never thought about this fd-recycling case, I think this change still
has value in avoiding the silent closing of some other file.

>
> [...snip...]
>