glibc 2.3.4 on DEC Alpha segfaults

[Jakub Bogusz]

On Sat, Apr 16, 2005 at 08:55:39PM -0400, Andrew A. Gill wrote:
> On Sat, 16 Apr 2005, Jakub Bogusz wrote:
> > On Tue, Apr 12, 2005 at 12:24:06AM +0200, Jakub Bogusz wrote:
> > > On Sun, Apr 10, 2005 at 11:50:41PM -0400, Andrew A. Gill wrote:
> > > > glibc is segfaulting on DEC Alpha for me.
> > > >
> > > > The last version that works is glibc-2.3.4-0.20040603.1.  The
> > > > later CVS versions and glibc-2.3.4-[12] fail.  gdb won't let me
> > > > do a backtrace (``no stack''), but I've got the following bits
> > > > from ltrace (strace is attached):
> > [...]
> > > > I'm not sure what's causing this--it may just be that my kernel
> > > > (2.6.11) isn't configured for NPTL (glibc-2.3.4-[12].alpha uses
> > > > NPTL, right?), or something easy.
> > >
> > > glibc 2.3.4-[12] uses NPTL "where available" (i.e. on 2.6.x kernels) and
> > > linuxthreads otherwise (when run on 2.4.x kernel).
> > >
> > > There may be some problem with NPTL - I didn't test such configuration
> > > as I have only 2.4.2x on alpha. dillo runs fine on glibc-2.3.4-1 with
> > > linuxthreads. You can try it on 2.6.x by exporting
> > > "LD_ASSUME_KERNEL=2.4.6" (and eventually use it as workaround until real
> > > fix comes).
> >
> > There were some NPTL problems indeed, even simple threaded programs
> > segfaulted.
> > Could you try glibc-2.3.5-0.3 from ac-test?
> 
> Yay!  It seems to work!
> 
> I'm curious--what did you change?  Was it something in the PLD
> packaging, or something in the source?

It was caused by tls_fix patch (taken from Fedora Core) not updated at
proper time - i.e. one linuxthreads/alpha change in patch didn't follow
nptl/alpha change done in sources before 2.3.4 release.
I hope I fixed it properly.

(This patch is needed to have both LinuxThreads and NPTL libraries
installed, selectable at runtime.
Unpatched glibc sources support only one threads library at a time, so
one would need to choose: NPTL or ability to boot system on 2.4.x
kernel/run some app incompatible with TLS/NPTL.)


-- 
Jakub Bogusz    http://cyber.cs.net.pl/~qboosh/