I have applyed patch from uml site for Fedora, but the boot process is 
hanging with just after mounting ext2 image. I have use Debian-3.0r0 and 
redhat 6.2 image from user mode linux site.  My system is a pc with 
Fedora 1 and lates 2.6 kernel from fedora develomment. Glibc 2.3.3-1

[knutjbj@knut linux]$ linux ubd0=root_fs.rh-6.2-full.pristine.20020312
Checking for the skas3 patch in the host...not found
Checking for /proc/mm...not found
tracing thread pid = 3784
Linux version 2.4.23-1um (root@knut) (gcc version 3.3.2 20031022 (Red 
Hat Linux 3.3.2-1)) #1 Fri Dec 26 15:26:29 CET 2003
On node 0 totalpages: 8192
zone(0): 8192 pages.
zone(1): 0 pages.
zone(2): 0 pages.
Kernel command line: ubd0=root_fs.rh-6.2-full.pristine.20020312 
root=/dev/ubd0
Calibrating delay loop... 814.78 BogoMIPS
Memory: 15504k available
Dentry cache hash table entries: 2048 (order: 2, 16384 bytes)
Inode cache hash table entries: 1024 (order: 1, 8192 bytes)
Mount cache hash table entries: 512 (order: 0, 4096 bytes)
Buffer cache hash table entries: 1024 (order: 0, 4096 bytes)
Page-cache hash table entries: 4096 (order: 2, 16384 bytes)
Checking for host processor cmov support...Yes
Checking for host processor xmm support...No
Checking that ptrace can change system call numbers...OK
Checking that host ptys support output SIGIO...Yes
Checking that host ptys support SIGIO on close...No, enabling workaround
Checking for /dev/anon on the host...Not available (open failed with 
errno 2)
POSIX conformance testing by UNIFIX
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society NET3.039
Initializing RT netlink socket
Starting kswapd
VFS: Disk quotas vdquot_6.5.1
Journalled Block Device driver loaded
Coda Kernel/Venus communications, v5.3.18, coda@cs.cmu.edu
devfs: v1.12c (20020818) Richard Gooch (rgooch@atnf.csiro.au)
devfs: boot_options: 0x0
Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
pty: 256 Unix98 ptys configured
Software Watchdog Timer: 0.05, timer margin: 60 sec
SLIP: version 0.8.4-NET3.019-NEWTTY (dynamic channels, max=256).
CSLIP: code copyright 1989 Regents of the University of California.
SLIP linefill/keepalive option.
RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
loop: loaded (max 8 devices)
PPP generic driver version 2.4.2
PPP Deflate Compression module registered
PPP BSD Compression module registered
Universal TUN/TAP device driver 1.5 (C)1999-2002 Maxim Krasnyansky
LVM version 1.0.7(28/03/2003)
Initializing software serial port version 1
mconsole (version 2) initialized on /home/knutjbj/.uml/d9Yqzp/mconsole
Partition check:
 ubda: unknown partition table
UML Audio Relay (host dsp = /dev/sound/dsp, host mixer = /dev/sound/mixer)
Initializing stdio console driver
NET4: Linux TCP/IP 1.0 for NET4.0
IP Protocols: ICMP, UDP, TCP
IP: routing cache hash table of 512 buckets, 4Kbytes
TCP: Hash tables configured (established 512 bind 1024)
IPv4 over IPv4 tunneling driver
GRE over IPv4 tunneling driver
ip_conntrack version 2.1 (121 buckets, 968 max) - 292 bytes per conntrack
ip_tables: (C) 2000-2002 Netfilter core team
ipt_recent v0.3.1: Stephen Frost <sfrost@snowman.net>.  
http://snowman.net/projects/ipt_recent/
arp_tables: (C) 2002 David S. Miller
NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
IPv6 v0.8 for NET4.0
IPv6 over IPv4 tunneling driver
ip6_tables: (C) 2000-2002 Netfilter core team
NET4: Ethernet Bridge 008 for NET4.0
IPVS: Connection hash table configured (size=4096, memory=32Kbytes)
IPVS: ipvs loaded.
IPVS: [rr] scheduler registered.
IPVS: [wrr] scheduler registered.
IPVS: [lc] scheduler registered.
IPVS: [wlc] scheduler registered.
IPVS: [lblc] scheduler registered.
IPVS: [lblcr] scheduler registered.
IPVS: [dh] scheduler registered.
IPVS: [sh] scheduler registered.
IPVS: [sed] scheduler registered.
IPVS: [nq] scheduler registered.
VFS: Mounted root (ext2 filesystem) readonly.
I'm tracing myself and I can't get out