Greetings,

I've grabed the 2.6.3 kernel source an applied uml-patch-2.6.3-rc2-1.bz2
as made available on the UML site @ SourceForge.  I've then configured the
kernel with a `make ARCH=um menuconfig`, compiled it with a `make ARCH=um
linux`, and tried to run it on a 2.4.23 skas3+fairsched patched host.  I
also added in an MPPE patch for PPTP-related stuff, which should be fine.

When I run the 2.6.3 binary, I get the following error to the console:

  VFS: Cannot open root device "ubd0" or unknown-block(0,0)
  Please append a correct "root=" boot option
  Kernel panic: VFS: Unable to mount root fs on unknown-block(0,0)

I'm calling the UML binary with the following command-line options:

  user$ ./linux-2.6.3.mppe.bin devfs=nomount mem=128M \
    ubd0=fedora-core1.disk \
    con0=fd:0,fd:1 con=/dev/null \
    eth0=tuntap,tap3 root=/dev/ubd0

It's not a permissions problem with the 'fedora-core1.disk' file, as this
file works just fine with a 2.4.x UML kernel, and it's an ext3 filesystem:

  [root@phobos linux-2.6.3]# grep EXT3 .config
  CONFIG_EXT3_FS=y
  CONFIG_EXT3_FS_XATTR=y
  CONFIG_EXT3_FS_POSIX_ACL=y
  # CONFIG_EXT3_FS_SECURITY is not set
  [root@phobos linux-2.6.3]# grep EXT2 .config
  CONFIG_EXT2_FS=y
  # CONFIG_EXT2_FS_XATTR is not set
  [root@phobos linux-2.6.3]# 

I've attached the complete kernel .config I used for this 2.6 compilation.

Any help would be very much appreciated.  Thanks, in advance.

--          _ 
__ __ ___ _| | William R. Lorenz <wrl@express.org> 
\ V  V / '_| | http://www.clevelandlug.net/ ; "Every revolution was 
 \./\./|_| |_| first a thought in one man's mind." - Ralph Waldo Emerson