Bug#613221: This is related to __thread

[Yavor Doganov <yavor@gnu.org>]

Eric Wasylishen wrote:
> I think what led me to say this was, I found that modifying
> GNUstep-gui so it links directly to cairo and pixman made the crash
> disappear.

Interesting.  But that's only a workaround, and not really an option
because gnustep-gui is configured with --as-needed in Debian (so
linking with unneded libraries doesn't happen), unless we deliberately
use cairo and pixman symbols.  Which looks way too hackish to me.

> Further supporting this, I tried to write a simple test case with a
> layout similar to GNUstep:
> 
> 1. executable, dynamically linked to:
> 2. shared library, which dlopens:
> 3. shared library, which uses TLS
> 
> and I was unable to get a crash to happen. 

I've done that too, both with a plain C and Objective-C program (to
see if the ObjC runtime is somehow involved).  No crash.

> Are you also observing it on 32-bit only?

Yes.  (I don't have a 64-bit machine to verify, though.)