Re: [uml-user] Instant Segfault when running UML

[Christoph D. <cdw...@gm...>]

On Wed, Dec 07, 2005 at 07:09:47PM +0100, Blaisorblade wrote:
> On Wednesday 07 December 2005 17:07, Christoph Dwertmann wrote:
> > Hi!
>=20
> > I'm trying to build my own UML kernel here. It builds fine, but
> > executing the kernel leads to:
>=20
> > GDB shows this:
>=20
> > Program received signal SIGSEGV, Segmentation fault.
> > 0xa028a2d5 in __libc_setup_tls ()
> > Current language:  auto; currently asm
> > (gdb) bt
> > #0  0xa028a2d5 in __libc_setup_tls ()
> > #1  0xa028a66f in __pthread_initialize_minimal ()
> > #2  0xa028a045 in __libc_start_main ()
> > #3  0xa0014021 in _start () at ../sysdeps/i386/elf/start.S:119
>=20
> Ok, it's due to some weird toolchain-related bug.
>=20
> > I've built kernels 2.4.23, 2.4.27, 2.4.28 and 2.6.14 with
> > Blaisorblade's UML patches. The host kernel is 2.6.15-rc5 vanilla, and
> > I'm running Debian sid (updated daily) on x86.
>=20
> Ok, it's a bug in some new binutils/GCC/glibc. While we try to debug the=
=20
> thing, can you post the releases of these 3 components? Also, can you upl=
oad=20
> somewhere and post the URL of your compressed "ld" binary?

Hi, thanks for your reply. Here's my configuration:

alderaan:~/uml# gcc --version
gcc (GCC) 4.0.3 20051201 (prerelease) (Debian 4.0.2-5)

alderaan:~/uml# dpkg -l | grep binutils
ii  binutils  2.16.1cvs20051117-1

alderaan:~/uml# dpkg -l | grep glibc
ii  libstdc++2.10-glibc2.2               2.95.4-24=20
(is this the package containing glibc?)

alderaan:~/uml# dpkg -l | grep libc6
ii  libc6                                2.3.5-8.1
ii  libc6-dev                            2.3.5-8.1

Grab my ld binary here:
http://www.informatik.uni-bremen.de/~nermal/ld.bz2

> Btw, to help with the current problem (while fixing the bug), have you an=
y=20
> need unsatisified by existing binaries (either on my site or on=20
> uml.nagafix.co.uk ?).

yeah I need to apply a few custom kernel patches, and maybe modify
them to fit my needs. I really need to be able to compile my own UML
kernels. But thanks for the offer!

> > Renaming /lib/tls does not help.
>=20
> Even doing that on the host? In this (exceptional) case, the result of th=
at=20
> may be useful.

I just re-checked that: it makes no difference.

I noticed that most of the people having this error use a recent
Debian or Gentoo system. The cause must be somewhere in my build
system, as precompiled binaries run.

Thanks,

Christoph