gdb and linuxthreads (A deadlock in linuxthreads.)

[H.J. Lu]

> 
> > I have verified that there was no third thread at all. There were only
> > 2 threads, the manager and the thread just sent a request to the
> > manager. It may be a race condition which can only happen on a SMP
> > machine.
> 
> Hmph.  That's interesting.  I'll try to think of a scenario that
> explains this.  Sometimes, I fear the memory subsystem doesn't
> implement strong ordering on memory accesses like it's supposed to do
> according to the docs...
> 
> At any rate, you'll find below the patches that change the signal used
> to report dead children.  The patches are against the current working
> sources on anoncvs@glibc.cygnus.com.  I haven't been able to test them
> on my home machine, but will test them tomorrow at work.  I'll also
> test what happens with gdb.  Maybe the extra signals don't break
> anything, just causing gdb to rescan the set of running threads
> unnecessarily.
> 

Are you sure you sent me all the changes? I don't think it is correct.
Did you miss something in restart.h?

Thanks.

H.J.