Re: [uml-user] question on running uml

[Stefano M. <ste...@op...>]

On Fri, Feb 10, 2006 at 05:24:41PM +0100, Blaisorblade wrote:
> On Friday 10 February 2006 16:58, Stefano Melchior wrote:
> > On Fri, Feb 10, 2006 at 10:52:28AM -0500, Jeff Dike wrote:
> > Hi Jeff,
> >
> > > On Fri, Feb 10, 2006 at 03:58:35AM -0700, Yu Yang wrote:
> > > > UML reports  errors similar to below:
> > > >
> > > > [42949373.440000] VFS: Cannot open root device "ubd" or
> > > > unknown-block(0,0) [42949373.440000] Please append a correct "root=
=3D"
> > > > boot option
> > > > [42949373.440000] Kernel panic - not syncing: VFS: Unable to mount =
root
> > > > fs on unknown-block(0,0)
>=20
> Jeff is seeing this unknown-block and this often suggests the problem he=
=20
> describes (Kbuild tend to reuse /boot/config-$(uname -r) even for=20
> cross-builds, which is wrong).
>=20
> > > Looks like you don't have the ubd driver configured.  Run
> > > 	linux --showconfig | grep UBD
> > >
> > > If that doesn't show BLK_DEV_UBD configured, mrproper the tree, then =
run
> > > defconfig ARCH=3Dum before building it.
> >
> > may it be that he did not specified correctly the identifier of the user
> > block dev?
> > I mean he should have run:
> >
> > # linux root=3D/dev/ubd0
>=20
> In my expierence, rootfs=3D/dev/ubd0 is ok, root=3D/dev/ubd0 is not (UML =
passes=20
> root=3D98:0). Anyway, the default "root=3D98:0" is ok.
Sorry, but I think this log could be explanatory of my idea:

ste@etinarcadiaego{/data}$ linux root=3D/dev/ubd
Checking that ptrace can change system call numbers...OK
Checking syscall emulation patch for ptrace...missing
Checking PROT_EXEC mmap in /tmp...OK
Checking for the skas3 patch in the host:
  - /proc/mm...not found
  - PTRACE_FAULTINFO...not found
  - PTRACE_LDT...not found
UML running in SKAS0 mode
Linux version 2.6.15 (st...@et...) (gcc version 4.0.3
20051201 (prerelease) (Debian 4.0.2-5)) #1 Thu Feb 9 16:49:51 CET 2006
Built 1 zonelists
Kernel command line: root=3D/dev/ubd
PID hash table entries: 256 (order: 8, 4096 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 29244k available
Security Framework v1.0.0 initialized
Mount-cache hash table entries: 512
Checking for host processor cmov support...Yes
Checking for host processor xmm support...No
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)
Using 2.6 host AIO
NET: Registered protocol family 16
mconsole (version 2) initialized on /home/ste/.uml/64tcXn/mconsole
Mapper v0.1
mmapper_init - find_iomem failed
ubd: Synchronous mode
VFS: Disk quotas dquot_6.5.1
Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
Initializing Cryptographic API
io scheduler noop registered
io scheduler anticipatory registered
io scheduler deadline registered
io scheduler cfq registered
RAMDISK driver initialized: 16 RAM disks of 8192K size 1024 blocksize
loop: loaded (max 8 devices)
nbd: registered device at major 43
NET: Registered protocol family 2
IP route cache hash table entries: 512 (order: -1, 2048 bytes)
TCP established hash table entries: 2048 (order: 1, 8192 bytes)
TCP bind hash table entries: 2048 (order: 1, 8192 bytes)
TCP: Hash tables configured (established 2048 bind 2048)
TCP reno registered
TCP bic registered
NET: Registered protocol family 8
NET: Registered protocol family 20
Initialized stdio console driver
Console initialized on /dev/tty0
Initializing software serial port version 1
 ubda: unknown partition table
VFS: Cannot open root device "ubd" or unknown-block(0,0)
Please append a correct "root=3D" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(0,0)

EIP: 0073:[<a0128de1>] CPU: 0 Not tainted ESP: 007b:40001fc0 EFLAGS:
00000246
    Not tainted
EAX: 00000000 EBX: 000001ba ECX: 00000013 EDX: 000001ba
ESI: 000001b7 EDI: 00000000 EBP: 00000000 DS: 007b ES: 007b
a08a7b9c:  [<a00370fc>] notifier_call_chain+0x1a/0x36
a08a7bb8:  [<a0029aef>] panic+0x4f/0xc7
a08a7bd0:  [<a000180f>] mount_block_root+0xad/0xc1
a08a7c24:  [<a0001937>] mount_root+0x49/0x4e
a08a7c44:  [<a00019f7>] prepare_namespace+0xbb/0xec
a08a7c4c:  [<a000d171>] init+0x0/0x10f
a08a7c50:  [<a000d1c9>] init+0x58/0x10f
a08a7c58:  [<a002140a>] run_kernel_thread+0x30/0x3b
a08a7c68:  [<a000d171>] init+0x0/0x10f
a08a7c74:  [<a00213f4>] run_kernel_thread+0x1a/0x3b
a08a7cec:  [<a0026c58>] schedule_tail+0x23/0x115
a08a7d00:  [<a00164f8>] new_thread_handler+0x7f/0xa7
a08a7d04:  [<a000d171>] init+0x0/0x10f
a08a7d60:  [<a0128de1>] kill+0x11/0x20


ste@etinarcadiaego{/data}$ linux --showconfig | grep UBD
CONFIG_BLK_DEV_UBD=3Dy
CONFIG_BLK_DEV_UBD_SYNC=3Dy

Am I right?

SteX

--=20
Stefano Melchior, GPG key =3D D52DF829 - <ste...@op...>
http://etinarcadiaego.dyndns.org    --     http://www.stex.name