https://bugs.freedesktop.org/show_bug.cgi?id=104306
--- Comment #13 from Michel Dänzer michel@daenzer.net --- (In reply to eric vz from comment #12)
[...] gdb glxinfo and set a breakpoint on dri2_validate_usage, but that method appears not to be called before the process hangs.
It's not called in the client but in the Wayland compositor process, or maybe in Xwayland.