Bug#901497: Reassigning to Xwayland

[Josh Triplett <josh@joshtriplett.org>]

On Thu, Jun 14, 2018 at 11:56:03PM -0700, Josh Triplett wrote:
> reassign 901497
> retitle 901497 Xwayland: hangs spinning on write and SIGALRM
> thanks
> 
> After further investigation, I can reproduce this with Mesa 18.0.5-1 as
> well, just not as often.
> 
> After encountering this issue, I managed to switch to a text console,
> and found that Xwayland was using 100% CPU. strace of the running
> Xwayland produced the attached strace, in which Xwayland appears to be
> spinning, running a zero-byte writev, and periodically processing a
> SIGALRM. Other threads appear to be blocked on futexes.

Forgot to attach the strace, sorry. Will provide one again next time it
happens, but it consisted entirely of "write(14, [], 0) = 0" on one
thread.