Re: [PATCH RESEND 1/2] KVM: Prevent module exit until all VMs are freed

On 3/15/22 16:43, Murilo Opsfelder Araújo wrote:

...

+    if (!try_module_get(kvm_chardev_ops.owner)) { +        r = -ENODEV; +        goto out_err; +    }

Doesn't this problem also affects the other functions called from kvm_dev_ioctl()?

Is it possible that the module is removed while other ioctl's are still running, e.g. KVM_GET_API_VERSION and KVM_CHECK_EXTENSION, even though they don't use struct kvm?

No, because opening /dev/kvm also adds a reference to the module. The problem is that create_vm creates another source of references to the module that can survive after /dev/kvm is closed.

Paolo