Hi,

I downloaded a root file system from:
http://www.stearns.org/uml-root/root_fs.fc-4-base.pristine.20050622.bz2
and followed the instructions in
http://www.stearns.org/uml-root/root_fs.fc-4-base.pristine.20050622.note
in order to extract it. I am able to mount it as a loop device without problems.
I applied the patch from
http://www.user-mode-linux.org/~blaisorblade/patches/guest/uml-2.6.13-bs2/uml-2.6.13-bs2.patch.bz2
to the 2.6.13 vanilla kernel and built a uml kernel with ext3 support not as a module.
Now when I run it I get the following error:

[cl@amber uml]$ ./vmlinux mem=160M ubd0=root_fs.2005062201 ubd1=swap root=/dev/ubd/0 con=pty con0=fd:0,fd:1
Checking for /proc/mm...not found
Checking for the skas3 patch in the host...not found
UML running in SKAS0 mode
Checking PROT_EXEC mmap in /tmp...OK
Adding 15347712 bytes to physical memory to account for exec-shield gap
[42949372.960000] Linux version 2.6.13-bs2 (cl@amber) (gcc version 4.0.1 20050727 (Red Hat 4.0.1-5)) #1 Fri Sep 30 13:10:14 IDT 2005
[42949372.960000] Built 1 zonelists
[42949372.960000] Kernel command line: mem=160M ubd0=root_fs.2005062201 ubd1=swap root=/dev/ubd/0 con=pty con0=fd:0,fd:1
[42949372.960000] PID hash table entries: 1024 (order: 10, 16384 bytes)
[42949372.960000] Dentry cache hash table entries: 32768 (order: 5, 131072 bytes)
[42949372.960000] Inode-cache hash table entries: 16384 (order: 4, 65536 bytes)
[42949372.960000] Memory: 153984k available
[42949373.210000] Security Framework v1.0.0 initialized
[42949373.210000] SELinux:  Initializing.
[42949373.210000] SELinux:  Starting in permissive mode
[42949373.210000] selinux_register_security:  Registering secondary module capability
[42949373.210000] Capability LSM initialized as secondary
[42949373.210000] Mount-cache hash table entries: 512
[42949373.220000] Checking for host processor cmov support...Yes
[42949373.220000] Checking for host processor xmm support...No
[42949373.220000] Checking that ptrace can change system call numbers...OK
[42949373.220000] Checking syscall emulation patch for ptrace...missing
[42949373.220000] Checking that host ptys support output SIGIO...Yes
[42949373.220000] Checking that host ptys support SIGIO on close...No, enabling workaround
[42949373.220000] Checking for /dev/anon on the host...Not available (open failed with errno 2)
[42949373.220000] NET: Registered protocol family 16
[42949373.230000] mconsole (version 2) initialized on /home/cl/.uml/aAKSzJ/mconsole
[42949373.230000] audit: initializing netlink socket (disabled)
[42949373.230000] audit(0.270:1): initialized
[42949373.230000] VFS: Disk quotas dquot_6.5.1
[42949373.230000] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[42949373.230000] SELinux:  Registering netfilter hooks
[42949373.280000] Initializing Cryptographic API
[42949373.280000] io scheduler noop registered
[42949373.280000] io scheduler anticipatory registered
[42949373.280000] io scheduler deadline registered
[42949373.280000] io scheduler cfq registered
[42949373.280000] RAMDISK driver initialized: 16 RAM disks of 16384K size 1024 blocksize
[42949373.280000] loop: loaded (max 8 devices)
[42949373.280000] nbd: registered device at major 43
[42949373.300000] NET: Registered protocol family 2
[42949373.430000] IP route cache hash table entries: 2048 (order: 1, 8192 bytes)
[42949373.430000] TCP established hash table entries: 8192 (order: 4, 65536 bytes)
[42949373.430000] TCP bind hash table entries: 8192 (order: 5, 229376 bytes)
[42949373.430000] TCP: Hash tables configured (established 8192 bind 8192)
[42949373.430000] TCP reno registered
[42949373.430000] TCP bic registered
[42949373.430000] Initializing IPsec netlink socket
[42949373.430000] NET: Registered protocol family 1
[42949373.430000] NET: Registered protocol family 17
[42949373.430000] Initialized stdio console driver
[42949373.430000] Console initialized on /dev/tty0
[42949373.430000]  ubda: unknown partition table
[42949373.560000]  ubdb: unknown partition table
[42949373.560000] VFS: Cannot open root device "ubd/0" or unknown-block(0,0)
[42949373.560000] Please append a correct "root=" boot option
[42949373.560000] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
[42949373.560000]
[42949373.560000] EIP: 0073:[<a0382721>] CPU: 0 Not tainted ESP: 007b:b7f7df9c EFLAGS: 00200246
[42949373.560000]     Not tainted
[42949373.560000] EAX: 00000000 EBX: 00000a1f ECX: 00000013 EDX: 00000a1f
[42949373.560000] ESI: 00000a1e EDI: 00000011 EBP: b7f7dfb8 DS: 007b ES: 007b
[42949373.560000] aae97ac0:  [<a006304d>] show_regs+0x309/0x378
[42949373.560000] aae97af0:  [<a002d1c3>] panic_exit+0x43/0x8c
[42949373.560000] aae97b20:  [<a0097206>] notifier_call_chain+0x2e/0x88
[42949373.560000] aae97b50:  [<a006d7df>] panic+0x9f/0x1f8
[42949373.560000] aae97b80:  [<a000231a>] mount_block_root+0x116/0x1cc
[42949373.560000] aae97bd0:  [<a00025ee>] mount_root+0x7e/0x94
[42949373.560000] aae97bf0:  [<a000266d>] prepare_namespace+0x69/0x224
[42949373.560000] aae97c00:  [<a001c3c7>] init+0x1d7/0x220
[42949373.560000] aae97c20:  [<a00227c5>] run_kernel_thread+0x59/0x74
[42949373.560000] aae97ce0:  [<a003538e>] new_thread_handler+0xd2/0x138
[42949373.560000] aae97d20:  [<b7f7f420>] 0xb7f7f420
[42949373.560000]
[42949373.560000]
[cl@amber uml]$

Any idea?

Thanks,

--
------------------------------------------------------
Etay Meiri
etay.meiri@gmail.com