The ArchZFS project distributes binary kernel images with ZFS integrated. I don't know what the legal situation is for that.
In my case, the Arch package is more of a "recipe maker". It fetches the Linux headers and the zfs source code and compiles this for local use. As far as they are concerned, there is no distribution of the resulting artifact. IANAL, but I think if there's an issue with that, then OpenZFS is basically never usable under Linux.
Other companies distributed kernels with zfs support directly, such as Ubuntu. I don't recall there being news of them being sued over this, but maybe they managed to work something out.
In my case, the Arch package is more of a "recipe maker". It fetches the Linux headers and the zfs source code and compiles this for local use. As far as they are concerned, there is no distribution of the resulting artifact. IANAL, but I think if there's an issue with that, then OpenZFS is basically never usable under Linux.
Other companies distributed kernels with zfs support directly, such as Ubuntu. I don't recall there being news of them being sued over this, but maybe they managed to work something out.