Comment 37 for bug 1918427

Revision history for this message
Ryan Harper (raharper) wrote : Re: [Bug 1918427] Re: curtin: install flash-kernel in arm64 UEFI unexpected

* dann frazier <email address hidden> [2021-03-18 16:30]:
> On Thu, Mar 18, 2021 at 12:25 PM Ryan Harper <email address hidden> wrote:
> >
> > * dann frazier <email address hidden> [2021-03-18 12:11]:
> > > On Thu, Mar 18, 2021 at 10:25 AM Ryan Harper <email address hidden> wrote:
> > > >
> > > > * dann frazier <email address hidden> [2021-03-17 20:30]:
> > > > > On Tue, Mar 16, 2021 at 10:05 AM Ryan Harper <email address hidden> wrote:
> > > > > >
> > > > > > Hi Dan,
> > > > > >
> > > > >
> > > > > 1) flash-kernel could get installed post-divert. In that case,
> > > > > flash-kernel's own postinst will cause it to run and then fail. This
> > > > > happens today if you start with a cloud image w/o flash-kernel
> > > > > pre-baked because Ubuntu's kernel recommends flash-kernel, causing it
> > > > > to be installed along with the kernel. Official cloud images happen to
> > > >
> > > > Hrm, so if we take a squashfs rootfs (with no flash-kernel present)
> > > > chroot into it and install the linux-image-generic package pulling in
> > > > flash-kernel this fails due to postinst of flash-kernel expecting
> > > > initramfs to already be generated? This doesn't seem like a curtin bug.
> > >
> > > If done so in a chroot that exposes the kernel interfaces (/proc &
> > > /sys) that claim to be hardware that requires the initramfs to be
> > > post-processed, yes.
> >
> > Maybe I'm missing something but if I install linux-image-generic
> > it populates /boot with vmlinuz-$version (and a few more things)
> > and /lib/modules/$version and the kernels postinst will invoke
> > update-initramfs. The /boot/initrd.img-$version is *generated* at
> > that time during the kernel's postinstall
> >
> > Now, in the arm case IIUC, the kernel package has a dep on flash-kernel
> > being present as it's "needed" to generate the initramfs ... so how can
> > flash-kernel's postinst *fail* if it is the tool that's generating said
> > initramfs file?
>
> What flash-kernel does is generate wrapped versions of *exisiting*
> vmlinuz and initrd.img files. It doesn't generate those files, rather
> post-processes them.
> The kernel doesn't depend on flash-kernel, it just recommends it like
> it does GRUB on x86.

Yes, I get that but it still looks like a packaging bug if dpkg installs
flash-kernel first and /boot is not populated with existing initrds; one
could easily see this happen in a debootstrap.

Is the "liveness" of the chroot what's tripping up flash-kernel? We
currently run inside a chroot which mounts /dev /proc /run and /sys; we
could drop those but it also seems reasonable to have flash-kernel not
expect existing initrds?