[plug] 2.6 Kernels, Upgrading from kernel with devfs, to kernel without

Timothy White weirdit at gmail.com
Wed Aug 3 23:09:59 WST 2005


Hi. I've noticed via googling that this problem has hit a lot of
people hard. Basically, when they use a kernel with devfs compiled in,
even if they are using udev, then goto using no devfs and just udev,
they can't boot.
You get a Kernel Panic similar to this.
---
VFS: Cannot open root device "hda7" or unknown-block(3,7)
Please append a correct "root=" option
Kernel panic: VFS: Unable to mount root fs on unknown-block(3,7)
---
This has just hit me and from what I can see, the problem appears to
be that /dev/ is empty because devfs isn't filing it with dev nodes,
and udev is obviously not running yet.
So what's the solution? If we start creating nodes in there then that
defeats the purpose of udev. If we compile in devfs then it can never
be removed from the kernel (it is obsolete) as udev can't work without
it unless we have static nodes!

So what is the solution? I really don't want to recompile with devfs
just so I can boot. There should be a better way otherwise devfs isn't
really obsolete. I hope someone has the answer.

Anyway, I'm off to recompile cause I really want a better kernel. :(

Tim



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