Re: [PATCH net-next] modules: allow modprobe load regular elf binaries

[Alexei Starovoitov]

On Fri, Mar 09, 2018 at 12:59:36AM +0000, Andy Lutomirski wrote:
> 
> Alexei, can you give an example use case?  I'm sure it's upthread
> somewhere, but I'm having trouble finding it.

at the time of iptable's setsockopt() the kernel will do
err = request_module("bpfilter");
once.
The rough POC code:
https://git.kernel.org/pub/scm/linux/kernel/git/ast/bpf.git/tree/net/ipv4/bpfilter/sockopt.c?h=ipt_bpf#n25

> Also, I just tested this concept a bit.  Depmod invoked explicitly on
> an ET_EXEC with a.ko extension gets mad, but depmod -a on a kernel
> that has a "module" like that seems to work fine.  Go figure.

right. that's with the current patch.
In v2 I require .modinfo section to make sure license is specified,
but depmod still not very happy:
$ depmod /lib/modules/`uname -r`/kernel/net/bpfilter/bpfilter.ko
depmod: ERROR: Bad version passed /lib/modules/4.16.0-rc4-00799-g1716f0aa3039-dirty/kernel/net/bpfilter/bpfilter.ko
I'm not sure it's worth to silence it, since
as you noticed 'depmod -a' works.