Subject: Re: bug#14569: 24.3.50; bootstrap fails on Cygwin

From: Eli Zaretskii <[email-masked]>
Date: Fri, 14 Jun 2013 21:16:44 +0300

> Date: Fri, 14 Jun 2013 10:45:47 -0700
> From: Paul Eggert <[email-masked]>
> Cc: [email-masked]
> 
> Cygwin developers, I'm worried about a Cygwin bug where
> pthread_kill may not send a signal to the correct thread.
> This bug may be causing Emacs to crash.  The Cygwin bug is
> discussed in this thread:
> 
> http://cygwin.com/ml/cygwin/2012-05/msg00472.html

Caveat: I'm not a Cygwin developer, and don't even use Cygwin.

> Emacs uses pthread_kill to redirect
> SIGCHLD to the main thread; if this is sent to a random
> thread instead, that could explain the random crashes.

It should be easy to instrument deliver_child_signal so that it prints
something when it redirects SIGCHLD, and then the Cygwin users could
see if there's such a report immediately before the crash, or at all.