Bug#655772: linux-image-3.1.0-1-686-pae: Aptitude upgrade of package version 3.1.6-1 -> 3.1.8-2 sent "dm_mod..." message error

[Ben Hutchings]

On Mon, 2012-01-16 at 00:07 +0100, Vladimir 'φ-coder/phcoder' Serbinenko
wrote:
> On 14.01.2012 04:53, Ben Hutchings wrote:
> > On Sat, 2012-01-14 at 02:06 +0100, Stéphane Aulery wrote:
> >> Package: linux-2.6
> >> Version: 3.1.8-2
> >> Severity: normal
> >>
> >> Dear Maintainer,
> >>
> >> When I have updated package linux-image-3.1.0-1-686-pae 3.1.6-1 to
> >> 3.1.8-2, aptitude sent some error messages like this :
> >>
> >> dm_mod: Unknown symbol scsi_verify_blk_ioctl (err 0)
> > [...]
> >
> > It looks like this is due to GRUB running os-prober.
> >
> > We do not bump the kernel ABI when adding symbols, because that is
> > backward-compatible with modules built for the earlier version.  But
> > loading new modules is liable to fail after an upgrade until the new
> > kernel is running (i.e. until the next reboot.)  So long as os-prober
> > relies on loading a bunch of modules, GRUB *must not* run os-prober in
> > its kernel postinst hook.
> That doesn't sound as a reasonable requirement. As I see this, such an 
> install, overwriting older modules botches currently running kernel 
> which can lead to other unexpected failures as well.

It doesn't; the kernel runs just fine.

This is just like upgrading libc6, when you might have to restart
daemons that use NSS.

> I think it would be 
> reasonable to have such updates versioned and have 3.1.X or 3.1.0-X as 
> Linux version rather than 3.1.0

No, because:
1. /boot would fill up really quickly (don't tell me about apt-get
autoremove; it specifically doesn't work for kernel images).
2. This would break out-of-tree modules every time.

Both of this problems are solveable, but it's not something we can just
change unilaterally.

Ben.

-- 
Ben Hutchings
When in doubt, use brute force. - Ken Thompson
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