[gentoo-user] Grub broke out of the blue

[gentoo-user] Grub broke out of the blue

[Nikos Chantziaras]

I've no idea how it broke, but after an emerge --sync, a kernel 
(gentoo-sources) update was there.  After I compiled the kernel, I did 
the usual "make modules_install && make install".  I edited grub.conf 
only to the point of changing the booted kernel to the new one (just a 
matter of changing -r1 to -r2 at the end of the kernel filename).  I 
reboot, Grub stops working.  It just displays "GRUB" and hangs there.

What might have cause this?  /boot is a 50MB ext3 partition with 14MB 
free.  I had to boot from a live CD and make sda1 bootable (Windows XP) 
so I can get online and burn a repair CD that supports ext4 (/).

Re: [gentoo-user] Grub broke out of the blue

[Stroller]

On 17 Feb 2009, at 04:17, Nikos Chantziaras wrote:

> I've no idea how it broke, but after an emerge --sync, a kernel  
> (gentoo-sources) update was there.  After I compiled the kernel, I  
> did the usual "make modules_install && make install".  I edited  
> grub.conf only to the point of changing the booted kernel to the new  
> one (just a matter of changing -r1 to -r2 at the end of the kernel  
> filename).  I reboot, Grub stops working.  It just displays "GRUB"  
> and hangs there.
>
> What might have cause this?


$ cat /var/log/portage/elog/sys-boot:grub-0.97-r6:20090117-194927.log
LOG: preinst

To avoid automounting and autoinstalling with /boot,
just export the DONT_MOUNT_BOOT variable.


WARN: postinst
*** IMPORTANT NOTE: you must run grub and install
the new version's stage1 to your MBR.  Until you do,
stage1 and stage2 will still be the old version, but
later stages will be the new version, which could
cause problems such as an unbootable system.
This means you must use either grub-install or perform
root/setup manually! For more help, see the handbook:
http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?part=1&chap=10#grub-install-auto

LOG: postinst
To interactively install grub files to another device such as a USB
stick, just run the following and specify the directory as prompted:
    emerge --config =grub-0.97-r6
Alternately, you can export GRUB_ALT_INSTALLDIR=/path/to/use to tell
grub where to install in a non-interactive way.

$


Stroller.

[gentoo-user] Re: Grub broke out of the blue

[Nikos Chantziaras]

Nikos Chantziaras wrote:
> I've no idea how it broke, but after an emerge --sync, a kernel 
> (gentoo-sources) update was there.  After I compiled the kernel, I did 
> the usual "make modules_install && make install".  I edited grub.conf 
> only to the point of changing the booted kernel to the new one (just a 
> matter of changing -r1 to -r2 at the end of the kernel filename).  I 
> reboot, Grub stops working.  It just displays "GRUB" and hangs there.
> 
> What might have cause this?  /boot is a 50MB ext3 partition with 14MB 
> free.  I had to boot from a live CD and make sda1 bootable (Windows XP) 
> so I can get online and burn a repair CD that supports ext4 (/).

Back.  Grub was booting inside a VM under XP even though it refused to 
boot for "real".  So I booted in a VM and reinstalled Grub from there. 
I'm left to wonder now how copying a new kernel into /boot with "make 
install" can possibly make Grub go fubar...

[gentoo-user] Re: Grub broke out of the blue

[Nikos Chantziaras]

Stroller wrote:
> 
> On 17 Feb 2009, at 04:17, Nikos Chantziaras wrote:
> 
>> I've no idea how it broke, but after an emerge --sync, a kernel 
>> (gentoo-sources) update was there.  After I compiled the kernel, I did 
>> the usual "make modules_install && make install".  I edited grub.conf 
>> only to the point of changing the booted kernel to the new one (just a 
>> matter of changing -r1 to -r2 at the end of the kernel filename).  I 
>> reboot, Grub stops working.  It just displays "GRUB" and hangs there.
>>
>> What might have cause this?
> 
> 
> $ cat /var/log/portage/elog/sys-boot:grub-0.97-r6:20090117-194927.log
> LOG: preinst

I did not update or re-install grub.  The only thing I did was compile a 
kernel and copy the kernel image to /boot.

Re: [gentoo-user] Re: Grub broke out of the blue

[Stroller]

On 17 Feb 2009, at 04:51, Nikos Chantziaras wrote:

> Stroller wrote:
>> On 17 Feb 2009, at 04:17, Nikos Chantziaras wrote:
>>> I've no idea how it broke, but after an emerge --sync, a kernel  
>>> (gentoo-sources) update was there.  After I compiled the kernel, I  
>>> did the usual "make modules_install && make install".  I edited  
>>> grub.conf only to the point of changing the booted kernel to the  
>>> new one (just a matter of changing -r1 to -r2 at the end of the  
>>> kernel filename).  I reboot, Grub stops working.  It just displays  
>>> "GRUB" and hangs there.
>>>
>>> What might have cause this?
>> $ cat /var/log/portage/elog/sys-boot:grub-0.97-r6:20090117-194927.log
>> LOG: preinst
>
> I did not update or re-install grub.  The only thing I did was  
> compile a kernel and copy the kernel image to /boot.

Sorry. The updated grub was only released in the last month or two, so  
I assumed this was the first time you had rebooted since.

Stroller.

Re: [gentoo-user] Grub broke out of the blue

[Neil Bothwick]

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On Tue, 17 Feb 2009 06:17:07 +0200, Nikos Chantziaras wrote:

> I've no idea how it broke, but after an emerge --sync, a kernel 
> (gentoo-sources) update was there.  After I compiled the kernel, I did 
> the usual "make modules_install && make install".  I edited grub.conf 
> only to the point of changing the booted kernel to the
> new one (just a matter of changing -r1 to -r2 at the end of the kernel
> filename).  I reboot, Grub stops working.  It just displays "GRUB" and
> hangs there.

Could you have inadvertently made more of a change to grub.conf than
that? Grub is notoriously fragile when it comes to its config file?

Why did you edit it in the first place? As you used make install,you will
have symlinks from vmlinuz and vmlinuz.old to the new and previous
kernels. Use these in GRUB and there's no need to edit anything.


-- 
Neil Bothwick

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Re: [gentoo-user] Grub broke out of the blue

[Roy Wright]

Nikos Chantziaras wrote:
> I've no idea how it broke, but after an emerge --sync, a kernel 
> (gentoo-sources) update was there.  After I compiled the kernel, I did 
> the usual "make modules_install && make install".  I edited grub.conf 
> only to the point of changing the booted kernel to the new one (just a 
> matter of changing -r1 to -r2 at the end of the kernel filename).  I 
> reboot, Grub stops working.  It just displays "GRUB" and hangs there.

I normally don't edit my grub.conf, instead I have entries for
vmlinuz and vmlinuz.old (make install updates these).

When I do edit grub.conf, I always run grub-install afterwards.
I don't know if this is necessary, but it's my habit...

HTH,
Roy

[gentoo-user] Re: Grub broke out of the blue

[Nikos Chantziaras]

Neil Bothwick wrote:
> On Tue, 17 Feb 2009 06:17:07 +0200, Nikos Chantziaras wrote:
> 
>> I've no idea how it broke, but after an emerge --sync, a kernel 
>> (gentoo-sources) update was there.  After I compiled the kernel, I did 
>> the usual "make modules_install && make install".  I edited grub.conf 
>> only to the point of changing the booted kernel to the
>> new one (just a matter of changing -r1 to -r2 at the end of the kernel
>> filename).  I reboot, Grub stops working.  It just displays "GRUB" and
>> hangs there.
> 
> Could you have inadvertently made more of a change to grub.conf than
> that? Grub is notoriously fragile when it comes to its config file?

No, the change was a simple change of 1 byte ("1" -> "2").


> Why did you edit it in the first place? As you used make install,you will
> have symlinks from vmlinuz and vmlinuz.old to the new and previous
> kernels. Use these in GRUB and there's no need to edit anything.

That won't work for me because I keep two different kernels (one for 
vmware and one for native) and I sometimes rebuild one of them after 
reconfiguring.  With that approach I would end up with the "Native" Grub 
entry trying to boot the vmware kernel.

One thing that could be at fault is that I had grub installed into hd0,2 
(sda3) which is an ext4 partition.  /boot is sda4 and is ext3.  But I'm 
sure grub should work no matter where you install it.  I can even 
install it on sda1 which is NTFS and it works.  Hell, I can even install 
it on the swap partition.

I guess the reason it broke will remain a mystery :P

Re: [gentoo-user] Grub broke out of the blue

[Dirk Heinrichs]

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Am Dienstag, 17. Februar 2009 05:44:07 schrieb Stroller:

> To avoid automounting and autoinstalling with /boot,
> just export the DONT_MOUNT_BOOT variable.

There's still a bug open to remove this stupid behaviour.

BTW: Once it's in your MBR, you can just "paludis --uninstall grub" (or 
whatever is its emerge equivalent ;-) )

Bye...

	Dirk

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Re: [gentoo-user] Re: Grub broke out of the blue

[Mick]

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On Tuesday 17 February 2009, Nikos Chantziaras wrote:

> One thing that could be at fault is that I had grub installed into hd0,2
> (sda3) which is an ext4 partition.  

I think that this is probably the cause.  GRUB has these stage 1.5 fs related 
files:

`e2fs_stage1_5'
`fat_stage1_5'
`ffs_stage1_5'
`jfs_stage1_5'
`minix_stage1_5'
`reiserfs_stage1_5'
`vstafs_stage1_5'
`xfs_stage1_5'

> /boot is sda4 and is ext3.  But I'm 
> sure grub should work no matter where you install it.  I can even
> install it on sda1 which is NTFS and it works.  Hell, I can even install
> it on the swap partition.

I think you are mixing stage 1 and stage 2 GRUB images?  Stage 1 is installed 
in MBR or any partition's boot sector.  No knowledge of fs is required for 
that to be accessed (by BIOS or a chainloader)  and JUMPTO deals with that.  
The 1.5 images on the other hand are used to read the fs in which GRUB's 
stage 2 is installed.  That's far too large to fit into a boot sector.  I 
doubt that GRUB's e2fs_stage1_5 can read ext4, but I don't know really - a 
question for GRUB's mailing list?

> I guess the reason it broke will remain a mystery :P

-- 
Regards,
Mick

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