Bug#497133: initramfs-tools: explodes when kernel is booted with root=mtd0

[Andres Salomon <dilinger@queued.net>]

On Mon, 1 Sep 2008 15:58:15 +0200
maximilian attems <max@stro.at> wrote:

> On Sat, 30 Aug 2008, Andres Salomon wrote:
> 
> > Package: initramfs-tools
> > Version: 0.92f
> > 
> > On OLPC machines, root is a nand device that is mounted as mtd0 (it
> > is neither a block device nor a char device).  The arguments passed
> > to the kernel are "ro root=mtd0 rootfstype=jffs2".
> 
> could you try to give the full device string root=/dev/mtd0
>  

Already tried that, it simply fails to find root then.  I also tried
root=/dev/mtdblock0, but that's not a real solution (mtd block emulation
is slower than just mtd).


> > Unfortunately, attempting to use an initrd based upon
> > initramfs-tools on such a machine results in a kernel panic and a
> > syntax error.
> > 
> > 
> > Begin: Mounting root file system ... /init: line 172: syntax error:
> > 0xmtd0
> > 
> > The probably appears to be in parse_numeric(); the init scripts
> > assume that normal devices are always prefixed with /, and root=
> > strings that aren't are raw device numbers (prefixing them with
> > 0x).  I'm not sure if there are other devices similar to mtd that
> > don't begin with a /.
> 
> parse_numeric is for legacy lilo support, right. does aboves
> circumvent it?
> 
> thanks for report!
>  

How about something like the following (untested) patch?  It's not foolproof,
but it at least ignores things that can't possibly be hex strings.



--- /usr//share/initramfs-tools/scripts/functions.orig	2008-09-01 11:14:11.000000000 -0400
+++ /usr//share/initramfs-tools/scripts/functions	2008-09-01 11:18:57.000000000 -0400
@@ -242,11 +242,14 @@ parse_numeric() {
 		minor=${1#*:}
 		major=${1%:*}
 		;;
-	*)
+	[A-Fa-f0-9]*)
 		value=$(( 0x${1} ))
 		minor=$(( ${value} % 256 ))
 		major=$(( ${value} / 256 ))
 		;;
+	*)
+		return
+		;;
 	esac
 
 	mknod -m 600 /dev/root b ${major} ${minor}