PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Erez Zilber]

Hi,

I've downloaded kernel 2.6.15-rc6 (had the same problem with rc7) and 
built it on RHAS 4:
make
make modules
make modules_install
make install

When I did that on an Opteron machine, after rebooting and selecting the 
2.6.15-rc6 entry in the grub menu, I get the following:

root (hd0,0)
Filesystem type is ext2fs, partition type 0x83
kernel /vmlinuz-2.6.15-rc6 ro root=/dev/VolGroup00/LogVol00 rhgb quiet 
console=ttyS0,115200 console=tty0
[Linux-bzimage, setup=0x1400, size=0x1dfa8c]
initrd /initrd--2.6.15-rc6.img
[Linux-initrd @ 0x37f20000, 0xcff3f bytes]

Uncompressing Linux... Ok, booting the kernel.
Kernel panic - not syncing: VFS: unable to mount root fs on 
unknown-block(0,0)

I made sure that ext2 is compiled with the kernel (not as a module).

When I do the same on an emt64 machine, everything works ok. Any idea?

Thanks
-- 

____________________________________________________________

Erez Zilber | 972-9-971-7689

Software Engineer, Storage Team

Voltaire – _The Grid Backbone_

__

www.voltaire.com <http://www.voltaire.com/>

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Arjan van de Ven]

On Thu, 2005-12-29 at 13:38 +0200, Erez Zilber wrote:
> Hi,
> 
> I've downloaded kernel 2.6.15-rc6 (had the same problem with rc7) and 

2.6.15-rc needs a newer udev version...

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Erez Zilber]

Arjan van de Ven wrote:

>On Thu, 2005-12-29 at 13:38 +0200, Erez Zilber wrote:
>  
>
>>Hi,
>>
>>I've downloaded kernel 2.6.15-rc6 (had the same problem with rc7) and 
>>    
>>
>
>2.6.15-rc needs a newer udev version...
>
>
>  
>

Redhat AS4 comes with udev 039. I couldn't find a newer rpm for this distribution, so I cannot replace the current udev rpm.  I've downloaded the latest udev sources from http://www.us.kernel.org/pub/linux/utils/kernel/hotplug/ and installed it but I still get the same errors.


Erez

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Arjan van de Ven]

On Thu, 2005-12-29 at 14:38 +0200, Erez Zilber wrote:
> Arjan van de Ven wrote:
> 
> >On Thu, 2005-12-29 at 13:38 +0200, Erez Zilber wrote:
> >  
> >
> >>Hi,
> >>
> >>I've downloaded kernel 2.6.15-rc6 (had the same problem with rc7) and 
> >>    
> >>
> >
> >2.6.15-rc needs a newer udev version...
> >
> >
> >  
> >
> 
> Redhat AS4 comes with udev 039. I couldn't find a newer rpm for this distribution, so I cannot replace the current udev rpm.  I've downloaded the latest udev sources from http://www.us.kernel.org/pub/linux/utils/kernel/hotplug/ and installed it but I still get the same errors.

after you get a recent enough udev you probably need to recreate a new
initrd (and pray that you don't need a newer mkinitrd to match the newer
udev...) since udev is also put inside the initrd.

To be fair, enterprise linux distributions aren't actually designed to
run brand spanking new kernels, and the vendors aren't likely to update
userland tools to make newer kernels work either (unlike, say,
distributions like Fedora Core or SuSE or .. or .. or .. )

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Erez Zilber]

Arjan van de Ven wrote:

>On Thu, 2005-12-29 at 14:38 +0200, Erez Zilber wrote:
>  
>
>>Arjan van de Ven wrote:
>>
>>    
>>
>>>On Thu, 2005-12-29 at 13:38 +0200, Erez Zilber wrote:
>>> 
>>>
>>>      
>>>
>>>>Hi,
>>>>
>>>>I've downloaded kernel 2.6.15-rc6 (had the same problem with rc7) and 
>>>>   
>>>>
>>>>        
>>>>
>>>2.6.15-rc needs a newer udev version...
>>>
>>>
>>> 
>>>
>>>      
>>>
>>Redhat AS4 comes with udev 039. I couldn't find a newer rpm for this distribution, so I cannot replace the current udev rpm.  I've downloaded the latest udev sources from http://www.us.kernel.org/pub/linux/utils/kernel/hotplug/ and installed it but I still get the same errors.
>>    
>>
>
>after you get a recent enough udev you probably need to recreate a new
>initrd (and pray that you don't need a newer mkinitrd to match the newer
>udev...) since udev is also put inside the initrd.
>
>To be fair, enterprise linux distributions aren't actually designed to
>run brand spanking new kernels, and the vendors aren't likely to update
>userland tools to make newer kernels work either (unlike, say,
>distributions like Fedora Core or SuSE or .. or .. or .. )
>
>
>  
>
So, I understand that, currently (until I get a a recent enough udev), 
2.6.15 cannot be used with RHAS-4 on Opteron machines. Anyway, thanks 
for your help.

Erez

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Andi Kleen]

Erez Zilber <erezz@voltaire.com> writes:
> >
> So, I understand that, currently (until I get a a recent enough udev),
> 2.6.15 cannot be used with RHAS-4 on Opteron machines. Anyway, thanks
> for your help.

I think that's too strong. udev setups are fragile and seem 
to be inventented by the devil to make kernel updates hell, but if you
just compile the needed drivers and file systems for root statically 
into the kernel it should work.  For network devices and other
drivers not needed for root you can either load them manually
early in a rc.d file or also compile them in.
 
Typically when udev goes wrong it just doesn't autoload the modules,
but still processes the events when devices appear.

-Andi

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Thomas Molina]

On Thu, 29 Dec 2005, Erez Zilber wrote:

> Hi,
> 
> I've downloaded kernel 2.6.15-rc6 (had the same problem with rc7) and built it
> on RHAS 4:
> 
> When I did that on an Opteron machine, after rebooting and selecting the
> 2.6.15-rc6 entry in the grub menu, I get the following:
> 
> Uncompressing Linux... Ok, booting the kernel.
> Kernel panic - not syncing: VFS: unable to mount root fs on unknown-block(0,0)
> 
> I made sure that ext2 is compiled with the kernel (not as a module).
> 
> When I do the same on an emt64 machine, everything works ok. Any idea?

Check on your /boot/grub.config.  The above error message is typically 
seen when the root= parameter points to a symbolic disk label instead of a 
specific disk such as /dev/hda1.  I'm not sure what the procedure for 
updating where the label points (possibly a mkinitrd) because I normally 
change the grub.conf to point to a specific disk.

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Arjan van de Ven]

On Fri, 2005-12-30 at 07:31 -0500, Thomas Molina wrote:
> On Thu, 29 Dec 2005, Erez Zilber wrote:
> 
> > Hi,
> > 
> > I've downloaded kernel 2.6.15-rc6 (had the same problem with rc7) and built it
> > on RHAS 4:
> > 
> > When I did that on an Opteron machine, after rebooting and selecting the
> > 2.6.15-rc6 entry in the grub menu, I get the following:
> > 
> > Uncompressing Linux... Ok, booting the kernel.
> > Kernel panic - not syncing: VFS: unable to mount root fs on unknown-block(0,0)
> > 
> > I made sure that ext2 is compiled with the kernel (not as a module).
> > 
> > When I do the same on an emt64 machine, everything works ok. Any idea?
> 
> Check on your /boot/grub.config.  The above error message is typically 
> seen when the root= parameter points to a symbolic disk label instead of a 
> specific disk such as /dev/hda1.  I'm not sure what the procedure for 
> updating where the label points (possibly a mkinitrd) because I normally 
> change the grub.conf to point to a specific disk.

there is no such procedure, because the disk labels are... ON THE DISK.
And the initrd reads them from all the disks at boot time to find the
one needed. This means that if your disk changes name (for example
because of a scsi bus order change or because of a different order you
load the device drivers... or even if you forget to compile the sata
drivers and suddenly the disk goes from /dev/sda to /dev/hda).... things
just remain working

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Ochal Christophe]

Arjan van de Ven wrote:

>On Fri, 2005-12-30 at 07:31 -0500, Thomas Molina wrote:
>  
>
>>On Thu, 29 Dec 2005, Erez Zilber wrote:
>>
>>    
>>
>>>Hi,
>>>
>>>I've downloaded kernel 2.6.15-rc6 (had the same problem with rc7) and built it
>>>on RHAS 4:
>>>
>>>When I did that on an Opteron machine, after rebooting and selecting the
>>>2.6.15-rc6 entry in the grub menu, I get the following:
>>>
>>>Uncompressing Linux... Ok, booting the kernel.
>>>Kernel panic - not syncing: VFS: unable to mount root fs on unknown-block(0,0)
>>>
>>>I made sure that ext2 is compiled with the kernel (not as a module).
>>>
>>>When I do the same on an emt64 machine, everything works ok. Any idea?
>>>      
>>>
>>Check on your /boot/grub.config.  The above error message is typically 
>>seen when the root= parameter points to a symbolic disk label instead of a 
>>specific disk such as /dev/hda1.  I'm not sure what the procedure for 
>>updating where the label points (possibly a mkinitrd) because I normally 
>>change the grub.conf to point to a specific disk.
>>    
>>
>
>there is no such procedure, because the disk labels are... ON THE DISK.
>And the initrd reads them from all the disks at boot time to find the
>one needed. This means that if your disk changes name (for example
>because of a scsi bus order change or because of a different order you
>load the device drivers... or even if you forget to compile the sata
>drivers and suddenly the disk goes from /dev/sda to /dev/hda).... things
>just remain working
>
>
>
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at  http://www.tux.org/lkml/
>  
>
Compile the kernel with support for your hardware built in, i'm assuming 
you eighter build the controller as a module or didn't built it at all

Re: PROBLEM: cannot boot 2.6.15-rc6 on Opteron machine

[Thomas Molina]

> >there is no such procedure, because the disk labels are... ON THE DISK.
> >And the initrd reads them from all the disks at boot time to find the
> >one needed. This means that if your disk changes name (for example
> >because of a scsi bus order change or because of a different order you
> >load the device drivers... or even if you forget to compile the sata
> >drivers and suddenly the disk goes from /dev/sda to /dev/hda).... things
> >just remain working
> >

Interesting.  I've been compiling my own kernels for quite some time and 
have never had a boot device end up anywhere except where I thought it 
should.  This includes during the 2.5 craziness when parts of ide support 
was rewritten at least twice.  

> >
> Compile the kernel with support for your hardware built in, i'm assuming you
> eighter build the controller as a module or didn't built it at all

Certainly this is the best advice.  Not only support for the hardware, but 
also ext3 journalling as well as ext2 support.  I think it may be possible 
to end up with ext2 builtin but ext3 journalling as modular.