sys-kernel-config.mount needs modprobe@configfs.service since systemd v246.7
(https://github.com/systemd/systemd/commit/
42cc2855), so the kernel configfs
fails to mount in the initrd.
\
"$systemdsystemunitdir"/sys-kernel-config.mount \
\
+ "$systemdsystemunitdir"/modprobe@.service \
"$systemdsystemunitdir"/kmod-static-nodes.service \
"$systemdsystemunitdir"/systemd-tmpfiles-setup.service \
"$systemdsystemunitdir"/systemd-tmpfiles-setup-dev.service \
/etc/systemd/journald.conf.d/*.conf \
/etc/systemd/system.conf \
/etc/systemd/system.conf.d/*.conf \
+ "$systemdsystemconfdir"/modprobe@.service \
+ "$systemdsystemconfdir/modprobe@.service.d/*.conf" \
/etc/hosts \
/etc/hostname \
/etc/nsswitch.conf \