how can I check whether the module is loaded successfully?

[BlackMage2]

how can I check whether the module is loaded successfully?

[eafer]

You can run (as root) lsmod | grep apfs.

[BlackMage2]

ohh ok, the module is stored at /var/lib/dkms/linux-apfs-rw/kernel-5.15.0-124-generic-x86_64/module/apfs.ko for example

but the command shows nothing, loading of the module always fails:

insmod: ERROR: could not insert module apfs.ko: Invalid module format

[eafer]

So it's the same as before? You don't get anything if you run dmesg?

[BlackMage2]

no, nothing

[eafer]

Is this ubuntu? They have a package for the driver, have you tried installing that?

[BlackMage2]

what packages?

[eafer]

https://launchpad.net/ubuntu/plucky/amd64/apfs-dkms

[kurtbahartr]

Okay, this will sound silly, but @BlackMage2 - Do you happen to be on UEFI firmware with have secure boot enabled? If so, don't forget to sign the module you just built and enroll the cert in MOK using mokutil.

Sometimes insmod and modprobe tend to pull up such ambiguous errors in such a case. Just earlier today, I faced a similar error with NVIDIA GPU drivers on Fedora ("NVIDIA kernel module missing. Falling back to nouveau.") until I realized I forgot to enroll the certs in MOK, so give it a shot if you haven't already.