bug#24201: 25.1.50; TLS connections sometimes hang

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  24201@debbugs.gnu.org
> Date: Mon, 19 Feb 2018 19:16:50 +0100
> 
> Paul Eggert <eggert@cs.ucla.edu> writes:
> 
> > Lars Ingebrigtsen wrote:
> >> #0  pthread_sigmask (how=0, newmask=<optimized out>, 
> >> oldmask=0x7fffffff8a60)
> >>      at ../sysdeps/unix/sysv/linux/pthread_sigmask.c:50
> >
> > When you say that Emacs "hangs" surely you don't mean that the call to
> > pthread_sigmask is hanging. So, can we assume that Emacs is
> > busy-waiting for something? Is the CPU pegged? What does the busy-wait
> > loop look like?
> 
> It's using 100% CPU, so it's busy-waiting, but every time I stop it,
> it's in that pthread_sigmask, as far as I'm able to tell...

And if you then say "continue" or "finish", does it exit from the
pthread_sigmask call?  If not, some other thread is spinning.