From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20020830 Description of problem: since 7.3, i've been using a kernel line in grub.conf similar to kernel /vmlinux... ro root=LABEL=/ hdb=ide-scsi having labelled /dev/hda1, my root partition, with the label "/". however, since i upgraded to the red hat updates version of kernel 2.4.20-2.2, specifying my root filesystem using "LABEL=/" causes the following at boot time: VFS: Cannot open root device "LABEL=/" or 00:00 Please append a correct "root=" option kernel panic: VFS: Unable to mount root fs on 00:00 i can get around this by editing the grub kernel line and substituting "root=/dev/hda1" and it will boot fine. but this shouldn't be necessary -- the LABEL option has worked for quite some time until 2.4.20-2.2. i have verified that all of the partitions are still properly labelled, and unique. in addition, one other participant on the redhat mailing list reported exactly the same error. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1. use a "LABEL=/" option in /etc/grub.conf 2. reboot 3. Actual Results: should boot properly Expected Results: kernel panic, see above Additional info:
does your grub.conf list an initrd ?
never mind, someone else on the redhat list suggested that it was the lack of an initrd file that was the problem. apparently, even though i had all the modules i needed built into the kernel, the initrd file was still necessary to be able to use a LABEL option in grub.conf. without one, it's necessary to use the explicit device name. at least, that's the way it looks, and things work fine now.
I can boot a custom redhat kernel without initrd if ext3 is compiled into the kernel. grub.conf has root=LABEL=/. The problem occurs with non redhat kernels (eg. fresh download from kernel.org). Perhaps redhat kernels have a certain configuration default which allows labels to be read?
the kernel doesn't use this. At all. you HAVE to have an initrd to use LABEL for root.
I had ext3 compiled into the kernel but still the problem persisted. But removing the root=LABEL=/ itself from grub.conf let my box boot fully without any issues.