Re: [Qemu-devel] Insta-segfault! i386-linux-user

[Alexander Graf <agraf@suse.de>]

On Sep 18, 2007, at 8:25 PM, Thayne Harbaugh wrote:

> On Tue, 2007-09-18 at 15:53 +0200, Ronald wrote:
>> Thayne Harbaugh schreef:
>>> Has anyone seen an insta-segfault with i386-linux-user qemu?  I've
>>> compiled qemu-0.9.0 as well as qemu-cvs (2007-09-18) with gcc-3.4  
>>> and
>>> -fno-strict-aliasing on an amd64 and I get this:
>>>
>>> ./i386-linux-user/qemu-i386 --help
>>> Segmentation fault
>>>
>>>> From GDB:
>>>
>>> Program received signal SIGSEGV, Segmentation fault.
>>> 0x0000000000000000 in ?? ()
>>> (gdb) bt
>>> #0  0x0000000000000000 in ?? ()
>>> #1  0x00000000600575ed in __libc_csu_init ()
>>> #2  0x00002b826c660ade in __libc_start_main () from /lib/libc.so.6
>>> #3  0x00000000600050e9 in _start ()
>
> <SNIP>
>
>>>
>> Yes, I had this problem too. U only compiled the program using the
>> 'user' parameters.
>
> I only compiled the 'user' portion because that's all I want.
>
>>  But to get the virtualisation going, you need to
>> compile at least one 'softmmu' (whatever that is). Doing that will
>> create the executable: qemu    (this is the executable you  
>> want :)   )
>
> Err, no.  I don't want full virtualization.
>
>> So I run Linux and I compile it with (and I really need it):
>>
>> i386-linux-user AND i386-softmmu     (i386 can be replaced with your
>> arch such as: ppc, sparc, x86_64, mips, mipsel and arm)
>>
>> That should create an executable called qemu (as stated before) which
>> should not segfault immediatly lol :)
>
> Thank you for your comments.  User virtualization doesn't require
> softmmu.  User virtualization translates the ops in the user space
> program and then jumps into the real kernel of the host operating  
> system
> when a syscall is made - it therefore doesn't need to virtualize  
> all of
> the hardware for I/O and the like.  Obviously this only works for
> running linux executables of one architecture on linux of possibly
> another architecture.
>
> I might mention that none of the other user-space architectures  
> segfault
> - just i386 - e.g. arm-linux-user/qemu-arm works just fine.
>
>
>
>

We had this on the list some months ago. As far as I recall this  
correctly the problem is the linker script. Just take a look at the  
suse source rpm where we replace that one, so it works with x86_64.  
Be prepared for breakage though, as linux-user on 64-Bit hosts does  
not work properly.

Cheers,

Alex