bug#25172: 26.0.50; Concurrency feature, sit-for doesn't work (crashing and unexpected behaviour)

[Eli Zaretskii]

> From: Elias Mårtenson <lokedhs@gmail.com>
> Date: Thu, 15 Dec 2016 11:30:54 +0800
> Cc: Clément Pit--Claudel <clement.pit@gmail.com>, 
>       25172@debbugs.gnu.org
> 
>  After applying that patch, it hasn't crashed yet. So either it fixes the 
> problem, or it's simply buch harder to
>  reproduce. So far so good. Thanks a lot!
> 
> I want to note that the thing that seems to fix it is the application of the 
> most recent suggestion.

Thanks, I pushed it now.

> In other words, if I roll back the application of the previous
> suggestion (removing the calls to clock_input ()/unblock_input()) it
> still seems to be stable.

Yes, it turns out acquiring Glib context is thread-safe (it uses a
mutex internally), so only one thread can ever acquire it.  Not
calling Glib functions when we failed to acquire context avoids both
the crashes in Glib and calling block_input/unblock_input from more
than one thread.

I guess we can now close this bug?

Thanks so much for your help in debugging this.