Re: linuxthreads 2.2.2 causes SEGV

[Dan Maas]

> > I just recompiled glibc-2.2.2 by putting back the pieces of code
> > which were removed (as indicated by Dan).  I can now compile
> > and run programs that use libpthread, BUT only if I statically
> > link with the threads library.  If I compile to use the dynamic
> > libpthread, I continue to get the SEGV in __pthread_alt_lock().

After further investigation I have concluded that LDT-based pthreads is
simply broken; either GCC's __register_frame_info() or glibc's
__libc_global_ctors() must be changed for it to work.

For those of you who just want a functional pthreads library, I have a
guaranteed fix: go to the bottom of
glibc-2.2.2/linuxthreads/sysdeps/i386/i686/pt-machine.h. Take the line that
says

#if __ASSUME_LDT_WORKS > 0

and change it to

#if 0

Then recompile and reinstall glibc. Pthreads will work again.

(this change simply disables the use of LDT for thread-specific data;
pthreads will fall back to its default implementation, which is slightly
slower but does not require any initialization).

Regards,
Dan