Bug#853855: di-utils: Kernel boot options containing a dot are not propagated to the installed system
On Fri, 2017-02-03 at 12:22 +0100, Emmanuel Kasper wrote:
> > > A kernel boot param like net.ifnames=0 will be skipped when the
> > > installer parses the boot option for setting the bootloader.
> > >
> > > Found in di-utils:
> > >
> > > # Skip module-specific variables
> > > varnodot="${var##*.*}"
> > > if [ "$varnodot" = "" ]; then
> > > continue
> > > fi
> > >
> > > So basically any option containing a dot is not propagated to the
> > > installed system. This was introduced by
> > > 7cf15980d714da8b958a73c93459ee09fdbb9415 ("Skip new module-
> > > specific
> > > parameters in user-params.")
> > >
> > > I found no documented or obvious reason for this behaviour.
> >
> > Sounds like the assumption was that any "foo.bar=baz" arguments
> > were
> > always to be used as the "bar=baz" option when loading the "foo"
> > module
> > (i.e. "modprobe foo bar=baz"), which I think the installer supports
> > (for convenience) but perhaps not the installed system (where they
> > should instead be in /etc/modules or /etc/modprobe.conf or similar)
> > does not?
> >
> > which I think the installer supports
> > (for convenience) but perhaps not the installed system (where they
> > should instead be in /etc/modules or /etc/modprobe.conf or similar)
>
> Thanks for the analysys, it looks like a very much plausible rationale
> behind this commit.
>
> If I understand you correctly, net.ifnames is understood as
> a kernel module option, and modules options are not propagated to the
> bootloader, because they "should" be configured in
> /etc/modprobe.d/my_module.
That's along the lines of what I think might be happening, yess
> Actually I might be missing something, but if for instance I need a
> kernel module option to make the installer boot on my hardware, like a
> radeon.modeset=0, I probably need this on the installed system as well ?
Correct, my (unchecked) assumption was that something in d-i would be
doing so.
You might find evidence of that in the fact that your net.ifnames=bar
ended up under /etc/ somewhere, either in /etc/modprobe.d/* or
/etc/modprobe.conf or /etc/modules.
It's only fair to warn you I might be talking BS here and reality is
nothing like that...
Ian.
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