Bug#771379: linux-image-3.16-0.bpo.3-amd64: backport kernels not booting when root file system is on an LVM volume

[lee <lee@yagibdah.de>]

Ben Hutchings <ben@decadent.org.uk> writes:

> On Sat, 2014-11-29 at 23:52 +0100, lee wrote:
> [...]
>> > I think that I can deal with this in the backport by either
>> > (a) removing linux-initramfs-tool as a dependency, or
>> > (b) adding a versioned alternate dependency on dracut, that is not
>> > satisfied by stable,
>> > though neither of those is very satisfactory.
>> 
>> (c) remove from dracut that it provides initramfs-tools and have the
>>     backports kernel require the backports initramfs-tools package
>> 
>> Apparently dracut doesn't exactly provide initramfs-tools for otherwise
>> the backports kernel wouldn't get stuck during boot when initramfs-tools
>> is not installed but dracut is while the root fs is on an LVM logical
>> volume.
>
> I tried using dracut for a while, and it did support booting from LVM
> without any need to explicitly configure that.  I don't know why it
> didn't work on your system, but that's a bug and not a fundamental
> reason why it shouldn't be allowed as an alternative to initramfs-tools.

Hm, then why doesn't it work for me?  How could I find out?

> [...]
>> And BTW, dracut has the huge advantage that you can explicitly exclude
>> modules from being included into the initrd image.  With
>> initramfs-tools, I still haven't found a way to exclude the bnx2 and
>> e1000e modules (other than moving them away from /lib/modules/ before
>> updating the initrd image and putting them back after).  They must not
>> be loaded so early because I'm passing network cards through to domUs,
>> which is impossible when their modules are loaded from the initrd image.
>
> It is possible, but you have to unbind them first, e.g.:
>     echo 0000:12:34.5 > /sys/bus/pci/drivers/e1000e/unbind

First load them, then unbind them, then unload them, then pass the
device through?

> You can also 'blacklist' the drivers through modprobe configuration so
> that they aren't automatically loaded as soon as the devices are found.

I tried blacklisting, and it didn't work.  It seems that blacklisting is
ignored for modules loaded from the initrd image.


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