[Bug 634736] sysctl.conf / sysctl.conf.d settings not read when modules are loaded

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=634736

--- Comment #20 from Bill Nottingham  ---
systemd automatically reapplies for anything loaded by
systemd-modules-load.service; it also has:

# Apply sysctl variables to network devices (and only to those) as they appear.

ACTION=="add", SUBSYSTEM=="net", KERNEL!="lo",
RUN+="/usr/lib/systemd/systemd-sysctl --prefix=/proc/sys/net/ipv4/conf/$name
--prefix=/proc/sys/net/ipv4/neigh/$name --prefix=/proc/sys/net/ipv6/conf/$name
--prefix=/proc/sys/net/ipv6/neigh/$name"

for network devices. It doesn't handle any cases outside of that.

Arguably, I could see modules registering their sysctl range somehow so you
could just do:

ACTION=="add", SUBSYSTEM=="module", RUN+="/usr/lib/systemd/systemd-sysctl
--prefix=/proc/sys/$kernel" (replace $kernel with whatever the variable is)

But that requires kernel changes.