Re: [uml-user] UML using 100% CPU after mounting root filesystem

[Jason C. <ja...@ja...>]

silly question, but I had a similar issue (cpu and ram) when my guest was 
running an FSCK. Are you running an fsck or is it idle?

-- 

Jason
The place where you made your stand never mattered. Only that you were there..
And still on your feet.

On Wed, 20 Jul 2005, Ruaidhri Power wrote:

> I've just upgraded UML, and came across this problem: when starting the
> guest, output stops after "VFS: Mounted root (ext3 filesystem)
> readonly." - at that point the guest takes 100% CPU, consuming both user
> and system time.
>
> The host is Debian sarge, running vanilla 2.6.12 with the
> skas-2.6.12-v8.2 patch.  The guest is vanilla 2.6.12 with Paolo's
> 2.6.12-bs7 patch, though I've verified the problem still occurs without
> that patch.  I can post the host and guest's .configs if needed.
>
> The problem occurs on my own images which previously worked on older UML
> versions, and I've also tried one of the images from the Sourceforge
> site.
>
> Has anyone any idea why this is happening?  If not, how should I go
> about debugging it to help the UML developers?
>
> The complication is that this is a headless box.  I've added `debug' to
> the kernel command line, but I don't get an xterm with gdb in.  Yes,
> xterm and gdb are installed and I've run xlogo to test that X11
> forwarding is working.  Running gdb as `gdb linux' doesn't seem to work
> because I keep receiving SIGTRAPs.  I've heard debugging in skas mode is
> hard, any pointers here?
>
> Thanks in advance for any help you can give.  Guest output follows:
>
>  ruaidhri@joni:~$ linux ubd1=swap eth0=tuntap,,,x.x.x.29 mem=768M
>  Checking for /proc/mm...found
>  Checking for the skas3 patch in the host...found
>  Checking PROT_EXEC mmap in /tmp...OK
>  Kernel virtual memory size shrunk to 32505856 bytes
>  Linux version 2.6.12-bs7 (ruaidhri@joni) (gcc version 3.3.5 (Debian 1:3.3.5-13)) #1 Wed Jul 20 12:32:41 IST 2005
>  Built 1 zonelists
>  Kernel command line: ubd1=swap eth0=tuntap,,,x.x.x.29 mem=768M root=98:0
>  PID hash table entries: 2048 (order: 11, 32768 bytes)
>  Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
>  Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
>  Memory: 467200k available
>  Mount-cache hash table entries: 512
>  Checking for host processor cmov support...Yes
>  Checking for host processor xmm support...No
>  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 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)
>  NET: Registered protocol family 16
>  mconsole (version 2) initialized on /home/ruaidhri/.uml/2JjIYf/mconsole
>  Netdevice 0 : TUN/TAP backend - IP = x.x.x.29
>  highmem bounce pool size: 64 pages
>  devfs: 2004-01-31 Richard Gooch (rg...@at...)
>  devfs: boot_options: 0x0
>  io scheduler noop registered
>  io scheduler anticipatory registered
>  io scheduler deadline registered
>  io scheduler cfq registered
>  loop: loaded (max 8 devices)
>  tun: Universal TUN/TAP device driver, 1.6
>  tun: (C) 1999-2004 Max Krasnyansky <ma...@qu...>
>  NET: Registered protocol family 2
>  IP: routing cache hash table of 8192 buckets, 64Kbytes
>  TCP established hash table entries: 131072 (order: 8, 1048576 bytes)
>  TCP bind hash table entries: 65536 (order: 6, 262144 bytes)
>  TCP: Hash tables configured (established 131072 bind 65536)
>  ip_tables: (C) 2000-2002 Netfilter core team
>  NET: Registered protocol family 1
>  NET: Registered protocol family 10
>  IPv6 over IPv4 tunneling driver
>  ip6_tables: (C) 2000-2002 Netfilter core team
>  NET: Registered protocol family 17
>  Initialized stdio console driver
>  Console initialized on /dev/tty0
>  Initializing software serial port version 1
>   /dev/ubd/disc0: unknown partition table
>   /dev/ubd/disc1: unknown partition table
>  kjournald starting.  Commit interval 5 seconds
>  EXT3-fs: mounted filesystem with ordered data mode.
>  VFS: Mounted root (ext3 filesystem) readonly.
>
>
>