1650 and VFS: unable to mount root fs

bscott@ntisys.com bscott at ntisys.com
Thu Dec 5 10:22:01 CST 2002

On Thu, 5 Dec 2002, at 9:42am, Lars.Lindbom at farmbio.uu.se wrote:
>> RAMDISK: Compressed image found at block 0
>> Freeing initrd memory: 245k freed
>> VFS: Mounted root (ext2 filesystem).

  That is the initrd (initial RAM disk) being mounted as the root
filesystem.  The initrd is loaded by the boot loader (usually LILO or GRUB),
using real-mode INT13 BIOS calls to read the disk.  The kernel cannot use
the BIOS for disk access -- it needs a native Linux driver.  The initrd will
contain the modules needed to access the root disk -- typically SCSI and/or
RAID drivers.

  Once the needed modules are loaded, the "real" root filesystem will be
mounted somewhere, and the pivot_root(2) system call will be invoked to
switch the two.  Unfortunately, the kernel does not emit a specific message
when this occurs.  All you can do is look for another filesystem being
mounted before init(8) starts.

>> SCSI subsystem driver Revision: 1.00

  That's the SCSI subsystem module being loaded from the initrd.

>> kmod: failed to exec /sbin/modprobe -s -k scsi_hostadapter, errno = 2

  That error is benign.  The kernel is trying to auto-load a module for the
SCSI host adapter, but module auto-loading does not get setup until the
"real" root filesystem is mounted.

>> scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.8
>>         <Adaptec aic7899 Ultra160 SCSI adapter>
>>         aic7899: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs
>> scsi1 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.8
>>         <Adaptec aic7899 Ultra160 SCSI adapter>
>>         aic7899: Ultra160 Wide Channel B, SCSI Id=7, 32/253 SCBs

  The above occurs when the devicer driver for your SCSI host adapter(s)  
load.  It indicates that the host adapter(s) have been found.

>> blk: queue c24c8a14, I/O limit 4095Mb (mask 0xffffffff)
>>   Vendor: FUJITSU   Model: MAM3367MC         Rev: 5A01
>>   Type:   Direct-Access                      ANSI SCSI revision: 03
>> blk: queue c24c8c14, I/O limit 4095Mb (mask 0xffffffff)
>>   Vendor: PE/PV     Model: 1x3 SCSI BP       Rev: 0.28
>>   Type:   Processor                          ANSI SCSI revision: 02

  Finally, the above indicates that the devices attached to your host
adapter(s) were also found.

> The standard kernels hang just before this, at the VFS: Mounted root (ext2
> filesystem)
> I guess.

  Forgive me, but what do you mean by "I guess".  Is the "VFS: Mounted root"  
message the last message the kernel emits before it hangs, or not?  :)  
Check your error messages *exactly* -- if needed, copy them down on paper,
and compare them to the regular boot.  Minor differences may provide us a
major clue.

  Without knowing more, I am guessing that your initrd is somehow borken.  
What command(s) did you use to build said initrd?  Also, what does your boot
loader configuration file look like?

Ben Scott <bscott at ntisys.com>
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