totally random "VFS: Cannot open root device"

totally random "VFS: Cannot open root device"

[0602]

Hi!

(Please CC me your answers as I am not subscribed.)

I have a problem with 2.6.14.3 kernel (but this probably isn't too 
version-specific). I have a kernel which succesfully boots on totally 
random basis (cca 70% is success). My root partition resides on a SATA 
disc connected to a controller on Intel 6300ESB ICH southbridge (mb 
Intel se7320vp2). There is a reiserfs 3 filesystem on my root partition. 
Without any changes to configuration (os or bios or whatever) I 
sometimes get:

VFS: Cannot open root device "801" or unknown block(8,1)

Could this be some timeout issue, or indication of crappy hw? I've tried 
this about 10 times (immediately ctrl+alt+del on successfull boot or 
reset button on aforementioned panic) and I saw no regularities in this 
misbehaviour.

I sincerely appreciate any advice anyone can give.

Thanks,

r.

Re: totally random "VFS: Cannot open root device"

[Keith Mannthey]

What SATA controler are you using in your box? What does lspci report?
It sounds to me like the driver you are using is not playing well with your
SATA controler or drive.  It could be related to crappy HW or a driver issue.

When you system boots the drive says online and behaves ok?  You just
see device trouble when you boot up correct?

Is it possible to capture the boot messages from a failed boot (serial console,
netconsole)?  It can tell alot about why no root fs was found.  Most likley
no disk were found by the SATA driver.

Thanks,

Keith

Re: totally random "VFS: Cannot open root device"

[Tejun Heo]

0602@eq.cz wrote:
> Hi!
> 
> (Please CC me your answers as I am not subscribed.)
> 
> I have a problem with 2.6.14.3 kernel (but this probably isn't too 
> version-specific). I have a kernel which succesfully boots on totally 
> random basis (cca 70% is success). My root partition resides on a SATA 
> disc connected to a controller on Intel 6300ESB ICH southbridge (mb 
> Intel se7320vp2). There is a reiserfs 3 filesystem on my root partition. 
> Without any changes to configuration (os or bios or whatever) I 
> sometimes get:
> 
> VFS: Cannot open root device "801" or unknown block(8,1)
> 
> Could this be some timeout issue, or indication of crappy hw? I've tried 
> this about 10 times (immediately ctrl+alt+del on successfull boot or 
> reset button on aforementioned panic) and I saw no regularities in this 
> misbehaviour.
> 
> I sincerely appreciate any advice anyone can give.
> 

[CC'ing linux-ide]

Hello, 0602.  :-)

Can you please post dmesg of a successful booting?  That will tell us 
which SATA controller/disks you are using.  Also, the boot log of a 
failed boot will be very helpful - the best way to get this is via 
serial console.  If you don't have access to serial console, taking note 
   / picture of the part where SATA detection fails will do too.

Also, when the machine boots successfully, does it work without 
generating disk related kernel logs?  Just perform any IO-heavy 
operations - cp'ing directories which contain large files, 
tar/untarring... - and see if the kernel complains about anyting.

-- 
tejun

Re: totally random "VFS: Cannot open root device"

[0602]

Hi,

(Please CC me your answers as I am not subscribed.)

Tejun Heo wrote:
[...]
> Can you please post dmesg of a successful booting?  That will tell us 
> which SATA controller/disks you are using.  Also, the boot log of a 
> failed boot will be very helpful - the best way to get this is via 
> serial console.  If you don't have access to serial console, taking note 
>   / picture of the part where SATA detection fails will do too.

I've placed the dmesg and the picture of panic here: http://26143.eq.cz/

> 
> Also, when the machine boots successfully, does it work without 
> generating disk related kernel logs?  Just perform any IO-heavy 
> operations - cp'ing directories which contain large files, 
> tar/untarring... - and see if the kernel complains about anyting.
> 

There are no signs of anything wrong in logs, all my IO tests passed ok.

Regards,

r.

Re: totally random "VFS: Cannot open root device"

[Keith Mannthey]

On 11/30/05, 0602@eq.cz <0602@eq.cz> wrote:

Best guess is driver initilization troubles. The screen shot only
dosen't really show anything besides it is broken. A full boot log
from the failed boot would be nice.  There were some recent SATA
change could you try the current 2.6.15-rc3 as well?

Thanks,
 Keith