Unable to mount /dev/root

Adam Lackorzynski adam at os.inf.tu-dresden.de
Thu May 1 14:20:27 CEST 2008


On Wed Apr 30, 2008 at 20:43:17 +0400, Igor V. Ruzanov wrote:
> >> # CONFIG_HOTPLUG is not set
> >
> > You need CONFIG_HOTPLUG for udev to work correctly, without this option
> > you may not get the device-nodes even if you compiled the right drivers
> > in your kernel.
> >
> Thanks for your hint! I set CONFIG_HOTPLUG to 'y'. Also i added some 
> derivative options:
> # CONFIG_HOTPLUG_PCI_CPCI_ZT5550 is not set
> With them some error messages were disapperred from boot log but the 
> system persists to be dropped into panic after rest of messages:
> mount: could not find filesystem /dev/root
> [...]
> switchroot: mount failed: No such file or directory
> Kernel panic - not syncing: No such file or directory
> For little debug i unpacked my initrd image and modified 'init' script 
> with several changes:
> mount -o defaults --ro -t ext3 sda1 /sysroot
> showlabels
> sleep 5
> where mount command was given in obvious way with telling of root device 
> (in my case its a /dev/sda1 which also i point it in l4linux26.cfg) and 
> showtables to show what are devices/partitions and their labels are 
> exactly seen by nash. Noone of sd{a|b} devices was listed during of 
> next boot log.
> my l4linux26.cfg looks like:
> sleep 1
> task "vmlinuz-2.6.24-l4" "earlyprintk=yes mem=512M ro root=/dev/sda1 l4env_rd=initrd-2.6.24-l4.img"
> all_sects_writable
> allow_vga
> i even tried to change root=/dev/sda1 with root=LABEL=/ as labeled my 
> /dev/sda1 partition.
> I suppose that my mistake could be in absence some kernel options that 
> might be very specific for my hardware configuration:
> CPU: Pentium Dual Core, 2GHz
> RAM: 2048 Mb
> Chipset: Intel G33 Express
> HDD: SATA, 250Gb
> or there is hypothetical way to 'dig' the problem from some another side ;)

Your hardware does not look special in any way.

Do you see output like

sd 0:0:0:0: [sda] 156301488 512-byte hardware sectors (80026 MB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
 sda: sda1 sda2

when the modules load? Especially the last line is important as it
states that the partitions were found.

Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/

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