Re: [PATCH v4l-utils v2 2/2] keytable: cannot load BPF decoders from udevd

[Sean Young <sean@mess.org>]

On Sun, Oct 27, 2019 at 02:54:51PM +0000, Sean Young wrote:
> On Sun, Oct 27, 2019 at 03:18:55PM +0100, Hans Verkuil wrote:
> > After this was installed on my debian system (running the 'testing' version
> > of debian) the laptop would no longer boot since the systemd-udevd service
> > failed to load.
> > 
> > My laptop runs systemd 242.
> > 
> > After removing the installed 50-rc_keymap.conf it worked again.
> > 
> > So either this file is no good, or it requires a newer systemd for it to
> > work.
> 
> I think I know what the problem is. On Fedora, for the systemd-udevd.service
> there is this setting.
> SystemCallFilter=@system-service @module @raw-io
> then 50-rc_keymap.conf adds:
> SystemCallFilter=bpf
> Which is concatenated to the end.
> 
> On the debian version of systemd, SystemCallFilter is not set. So
> SystemCallFilter=bpf
> means that only the bpf syscall is allowed. 
> 
> I'm not sure what the correct solution is. I'll try a few things and if I
> don't come up with anything, I'll have to revert.
> 
> Suggestions welcome :)

I think this could be solved by having configure check for SystemCallFilter,
like so:

	grep -s SystemCallFilter /lib/systemd/system/systemd-udevd.service 

and then installing the override if needed. I'll try to do this in the next
few days.

Thanks,
Sean