Re: [uml-user] uml stuck on "Locating the top of the address space"

[Joakim A. <jo...@ar...>]

To debug, I ran UML in gdb. It segfaulted once during finding the bottom
limit, which is expected I guess.

I then interrupted it a couple of times while hanging on finding the top.
All interrupts hit the same line of code in task_size.c, so I think it's
stuck on the single line.

line 32 in
http://lxr.free-electrons.com/source/arch/x86/um/os-Linux/task_size.c
n = *address;

Does this tell you anything?


Locating the bottom of the address space ...
Program received signal SIGSEGV, Segmentation fault.
0x08078b9b in page_ok (page=<value optimized out>) at
arch/x86/um/os-Linux/task_size.c:32
32 arch/x86/um/os-Linux/task_size.c: No such file or directory.
in arch/x86/um/os-Linux/task_size.c
(gdb) c
Continuing.
0x0
Locating the top of the address space ... ^C
Program received signal SIGINT, Interrupt.
0x08078b9b in page_ok (page=<value optimized out>) at
arch/x86/um/os-Linux/task_size.c:32
32 in arch/x86/um/os-Linux/task_size.c



On Sun, Feb 12, 2012 at 3:41 PM, richard -rw- weinberger <
ric...@gm...> wrote:

> On Mon, Feb 13, 2012 at 12:29 AM, Joakim Arfvidsson
> <jo...@ar...> wrote:
> > Yes, the CPU is pegged while this is happening. I've left it for an hour
> > with no results.
> >
> > I looked at that code and couldn't really see a good reason for it to
> block
> > forever, except if the address space was so large it took a long time to
> get
> > through.
>
> Can you please very this?
> Just add a printf()...
>
> > The host kernel is 2.6.32-220.4.1.el6.i686 #1 SMP
> >
> > This is an Amazon EC2 instance, and I just found one hilarious workaround
> > for this. If I remove the "user-data" from the instance, UML starts
> working
> > again. User-data is a string that EC2 makes available to the running
> > instance as the response of an http request to a fake ip.
> >
>
> ???
>
> --
> Thanks,
> //richard
>