Hi,

I've been trying to get user-mode-linux running a reasonably recent linux setup in Amazon's EC2.  The host is required to be Amazon's 2.6.16-xenU kernel.  In my case, it's running Ubuntu Gutsy.  The guest is the version of UML that comes with Ubuntu, 2.6.22-rc5.

I think the problem must be with the libc.  If I use an older libc on both the host and the guest, I can get it running.  With a newer libc on the guest, it locks up after mounting the root fs.  With a newer libc on the host, I get the error pasted below.  Any help would be appreciated!

Core dump limits :
        soft - 0
        hard - NONE
Checking that ptrace can change system call numbers...OK
Checking syscall emulation patch for ptrace...OK
Checking advanced syscall emulation patch for ptrace...OK
Checking for tmpfs mount on /dev/shm...OK
Checking PROT_EXEC mmap in /dev/shm/...OK
Checking for the skas3 patch in the host:
  - /proc/mm...not found: No such file or directory
  - PTRACE_FAULTINFO...not found
  - PTRACE_LDT...not found
UML running in SKAS0 mode
[42949372.960000] Linux version 2.6.22-rc5 (root@vernadsky) (gcc version 4.1.3 20070629 (prerelease) (Ubuntu 4.1.2-13ubuntu2)) #2 Mon Jul 2 10:14:22 GMT 2007
[42949372.960000] Built 1 zonelists.  Total pages: 8128
[42949372.960000] Kernel command line: ubd0=laforge-root.img root=98:0
[42949372.960000] PID hash table entries: 128 (order: 7, 512 bytes)
[42949372.960000] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
[42949372.960000] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
[42949372.960000] Memory: 29312k available
[42949374.140000] Mount-cache hash table entries: 512
[42949374.140000] Checking for host processor cmov support...Yes
[42949374.140000] Checking for host processor xmm support...No
[42949374.140000] Checking that host ptys support output SIGIO...Yes
[42949374.140000] Checking that host ptys support SIGIO on close...No, enabling workaround
[42949374.140000] Using 2.6 host AIO
[42949374.140000] NET: Registered protocol family 16
[42949374.140000] NET: Registered protocol family 2
[42949374.430000] IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
[42949374.430000] TCP established hash table entries: 1024 (order: 1, 8192 bytes)
[42949374.430000] TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
[42949374.430000] TCP: Hash tables configured (established 1024 bind 1024)
[42949374.430000] TCP reno registered
[42949374.490000] Checking host MADV_REMOVE support...OK
[42949374.490000] mconsole (version 2) initialized on /root/.uml/mHLBJP/mconsole
[42949374.490000] Mapper v0.1
[42949374.490000] mmapper_init - find_iomem failed
[42949374.490000] UML Watchdog Timer
[42949374.490000] Host TLS support detected
[42949374.490000] Detected host type: i386
[42949374.490000] VFS: Disk quotas dquot_6.5.1
[42949374.490000] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[42949374.490000] JFS: nTxBlock = 229, nTxLock = 1832
[42949374.490000] SGI XFS with ACLs, security attributes, realtime, large block numbers, no debug enabled
[42949374.490000] SGI XFS Quota Management subsystem
[42949374.490000] io scheduler noop registered
[42949374.490000] io scheduler anticipatory registered (default)
[42949374.490000] io scheduler deadline registered
[42949374.490000] io scheduler cfq registered
[42949374.650000] SoftDog: cannot register miscdev on minor=130 (err=-16)
[42949374.650000] TCP cubic registered
[42949374.650000] NET: Registered protocol family 1
[42949374.650000] NET: Registered protocol family 17
[42949374.650000] Initialized stdio console driver
[42949374.650000] Console initialized on /dev/tty0
[42949374.650000] Initializing software serial port version 1
[42949374.710000]  ubda: unknown partition table
[42949374.750000] VFS: Mounted root (ext2 filesystem) readonly.
[42949374.950000] Kernel panic - not syncing: start_userspace : expected SIGSTOP, got status = 2943
[42949374.950000]
[42949374.950000] EIP: 0073:[<bfffe402>] CPU: 0 Not tainted ESP: 007b:b7de4fc0 EFLAGS: 00200246
[42949374.950000]     Not tainted
[42949374.950000] EAX: 00000000 EBX: 00000ab2 ECX: 00000013 EDX: 00000ab2
[42949374.950000] ESI: 00000aae EDI: 00000011 EBP: b7de4fd8 DS: 007b ES: 007b
[42949374.950000] 08327e0c:  [<0806ce8c>] show_regs+0xb4/0xb9
[42949374.950000] 08327e38:  [<0805b038>] panic_exit+0x25/0x3f
[42949374.950000] 08327e4c:  [<0807c418>] notifier_call_chain+0x21/0x46
[42949374.950000] 08327e6c:  [<0807c4b3>] __atomic_notifier_call_chain+0x17/0x19
[42949374.950000] 08327e88:  [<0807c4ca>] atomic_notifier_call_chain+0x15/0x17
[42949374.950000] 08327ea4:  [<08071532>] panic+0x52/0xd8
[42949374.950000] 08327ec4:  [<0806a3f3>] start_userspace+0xd0/0x11c
[42949374.950000] 08327ee4:  [<0805b32a>] init_new_context_skas+0x107/0x14a
[42949374.950000] 08327f04:  [<080ae8da>] do_execve+0x89/0x1cb
[42949374.950000] 08327f24:  [<08057ced>] execve1+0x2a/0x54
[42949374.950000] 08327f48:  [<08057d2c>] um_execve+0x15/0x41
[42949374.950000] 08327f64:  [<08059e25>] kernel_execve+0x2c/0x37
[42949374.950000] 08327f84:  [<080576cf>] run_init_process+0x1b/0x20
[42949374.950000] 08327f98:  [<08057764>] init_post+0x90/0xb8
[42949374.950000] 08327fa4:  [<08049879>] kernel_init+0x7e/0x85
[42949374.950000] 08327fb4:  [<08067315>] run_kernel_thread+0x37/0x42
[42949374.950000] 08327fe0:  [<0805b49d>] new_thread_handler+0x57/0x7e
[42949374.950000] 08327ffc:  [<a55a5a5a>] 0xa55a5a5a
[42949374.950000]
Segmentation fault


--
Steven Hazel
sah@awesame.org