Re: [HURD, PATCH] Fix stack switching at initialization time

[Ludovic Courtès]

Hi,

Thomas Schwinge <thomas@schwinge.name> skribis:

> On Fri, 22 Jul 2011 17:53:12 +0200, ludo@gnu.org wrote:
>> Pushed a slightly different version, thanks!
>> 
>> http://git.savannah.gnu.org/cgit/hurd/glibc.git/commit/?h=t/init-first.c&id=53b56b1101fc9bb4f295f23f54e7e19f8da8da16
>
> Just a heads-up, and I'm afraid, but with this patch I get:
>
>     $ ./testrun.sh ./libc.so
>     Segmentation fault
>
> Undoing it (see below), I'm back in service:
>
>     $ ./testrun.sh ./libc.so
>     GNU C Library development release version 2.11.90, by Roland McGrath et 
> al.
>     [...]
>
> This is still based on 2010-04 glibc sources, GCC 4.4, and old binutils
> 2.20.1.

The patch solved a problem for me with GCC 4.5 and Binutils 2.21.

> Perhaps it'd really be best to write this in a few lines of assembly?

Perhaps.

OTOH, it’s really a compiler bug if __builtin_frame_address or
__builtin_return_address don’t behave as advertised.  It should
definitely be more reliable than fiddling with the address of local
variables.

Thanks,
Ludo’.