loading vmw_vsock_virtio_transport by systemd breaks vsock_loopback autoloading

Hi all,

there is a systemd bug [1] which causes vsock_loopback not to be autoloaded due previous loading vmw_vsock_virtio_transport in an early phase of boot. vmw_vsock_virtio_transport requires vmw_vsock_virtio_transport_common and vsock, vsock_loopback requires vsock.

Reproducer: [2].
Proposed fix in systemd: [3]

While I think the bug should be fixed in systemd with proposed fix [3] we'd like to know opinion of the kernel vsock developers in case there is a way to improve vsock modules autoloading.

Quoted 9 lines

Hi all,

there is a systemd bug [1] which causes vsock_loopback not to be autoloaded due previous loading vmw_vsock_virtio_transport in an early phase of boot. vmw_vsock_virtio_transport requires vmw_vsock_virtio_transport_common and vsock, vsock_loopback requires vsock.

Reproducer: [2].
Proposed fix in systemd: [3]

Quoted 3 lines

While I think the bug should be fixed in systemd with proposed fix [3] we'd like to know opinion of the kernel vsock developers in case there is a way to improve vsock modules autoloading.

The original idea of vsock_loopback was to be used just for testing/debugging, so maybe even the autoloading when no other transport was loaded wasn't a great idea, but at the time we thought it might be useful for testing.

In general, therefore, if you want to use the loopback, it's always best to load vsock_loopback.

What use case is being affected by the fact that vsock_loopback isn't loaded automatically?

Thanks,
Stefano