[Pm-utils] [patch] disable suspend when kernel image changed

[Rafael J. Wysocki]

On Thursday 08 April 2010, Nigel Cunningham wrote:
> Hi.
> 
> On 08/04/10 20:25, Richard Zidlicky wrote:
> > On Thu, Apr 08, 2010 at 07:06:31PM +1000, Nigel Cunningham wrote:
> >> On 08/04/10 05:52, Richard Zidlicky wrote:
> >>> Hi,
> >>>
> >>> trying to fix this crash situation: /boot/vmlinuz-XXX exists and is the currently
> >>> running kernel, I decide to reconfigure and recompile it, overwrite /boot/vmlinuz-XXX
> >>> and hit pm-hibernate.
> >>>
> > ...
> > ...
> >>>
> >>> --- 01grub.rz   2010-04-07 19:52:02.000000000 +0200
> >>> +++ 01grub      2010-04-07 21:22:30.000000000 +0200
> >>> @@ -15,6 +15,7 @@
> >>>
> >>>           [ -x /sbin/grubby -a -x /sbin/grub ] || return $NA
> >>>           [ -e "/boot/vmlinuz-$(uname -r)" ] || return 1
> >>> +       [ /var/log/boot.log -ot "/boot/vmlinuz-$(uname -r)" ]&&   return $NA
> >>>           out=$(/sbin/grubby --info /boot/vmlinuz-$(uname -r) |grep index)
> >>>           [ -n "${out}" ] || return 1
> >>>           current=${out#index=}
> >>
> >> With anything relatively recent (post about 2.6.27 IIRC), this should be
> >> unnecessary. Code has been added so that you can hibernate with one
> >> kernel and resume with another.
> >
> > definitely not the case - just triggered it with 2.6.33.2 yesterday:
> >
> > Apr  7 16:23:45 localhost kernel: [   23.188781] Freezing user space processes ... (elapsed 0.01 seconds) done.
> > Apr  7 16:23:45 localhost kernel: [   23.199054] Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done.
> > Apr  7 16:23:45 localhost kernel: [   23.222282] PM: Loading image data pages (182231 pages) ...
> > Apr  7 16:23:45 localhost kernel: [   23.222310] PM: Image mismatch: version
> > Apr  7 16:23:45 localhost kernel: [   23.222355]
> > Apr  7 16:23:45 localhost kernel: [   23.222378] PM: Read 728924 kbytes in 0.01 seconds (72892.40 MB/s)
> > Apr  7 16:23:45 localhost kernel: [   23.222433] PM: Restore failed, recovering.
> > Apr  7 16:23:45 localhost kernel: [   23.230013] Restarting tasks ... done.
> > Apr  7 16:23:45 localhost kernel: [   24.047245] EXT3-fs (dm-6): recovery required on readonly filesystem
> >
> > it was exactly the same kernel release - only slightly reconfigured&  recompiled.
> 
> Hmm. My apologies; you're absolutely right.
> 
> I'll have to email Rafael (cc'd) - I'm not sure why that check is still 
> there. I know it is possible for you to hibernate one kernel and resume 
> from another - I've done it with TuxOnIce using the low-level code 
> Rafael put in. Perhaps he's discovered something that makes it 
> unreliable or such like.

That still should work, although only on x86-64, because I've never had the
time to implement it on x86-32.

That said, I haven't tried it myself recently and the feature might regress due
to the general x86 change flow.

Thanks,
Rafael