[Bug 58305] New: Sonny (RPG game) randomly freezes during gameplay

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=58305

Bug ID: 58305
           Summary: Sonny (RPG game) randomly freezes during gameplay
           Product: Wine
           Version: 10.8
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: wineserver
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Sonny, a game on Unity engine, started randomly freezing during gameplay after
I've updated WINE from v9.18 to v10.8. The game stops accepting input and even
the audio stops playing. But if I move mouse out of the WINE virtual desktop
and back in, the game starts working again.

Here's what CPU usage looks like during normal play and frozen state:

Normal:
- SonnyWindows.exe: 37% CPU
- wineserver: 8% CPU

Frozen:
- SonnyWindows.exe: 1% CPU
- wineserver: 100% CPU

I've managed to bisect the issue to the following commit:

commit 87ca5db40e2c1b37423bdc25101a5c5e39e67e6f
server: Use epoll_pwait2 for the main loop on Linux.

If I comment out #define HAVE_EPOLL_PWAIT2 1 in config.h and recompile WINE,
the problem goes away.

Game link: https://armor-games-studios.itch.io/sonny

I use Gentoo Linux. The issue may be reproducible in other Unity games as well.