Crash (Failed to call XSendEvent after wakeup: XError) on servo running WebGL content on X11

[Manishearth]

Just tried running the threejs examples on my linux desktop, and got the following crash:

[10:59:17] मanishearth@aperture ~/mozilla/servo O_o 
$ ./mach run -r https://threejs.org/examples/webgl_animation_cloth.html
THREE.WebGLRenderer: WEBGL_depth_texture extension not supported.
[2020-01-21T18:59:26Z ERROR canvas::canvas_data] Unimplemented canvas2d.fillText. Values received: FPS, 3, 2, None.
[2020-01-21T18:59:26Z ERROR canvas::canvas_data] Unimplemented canvas2d.fillText. Values received: MS, 3, 2, None.
[2020-01-21T18:59:27Z ERROR canvas::canvas_data] Unimplemented canvas2d.fillText. Values received: 253 MS (253-253), 3, 2, None.
[2020-01-21T18:59:27Z ERROR winit::platform::platform] X11 error: XError {
    description: "BadValue (integer parameter out of range for operation)",
    error_code: 2,
    request_code: 154,
    minor_code: 16,
}
[2020-01-21T18:59:27Z ERROR winit::platform::platform] X11 error: XError {
    description: "BadValue (integer parameter out of range for operation)",
    error_code: 2,
    request_code: 154,
    minor_code: 16,
}
Failed to call XSendEvent after wakeup: XError { description: "BadValue (integer parameter out of range for operation)", error_code: 2, request_code: 154, minor_code: 16 } (thread WRRenderBackend#0, at src/libcore/result.rs:1188)
stack backtrace:
[2020-01-21T18:59:27Z ERROR canvas::canvas_data] Unimplemented canvas2d.fillText. Values received: 25 MS (25-253), 3, 2, None.
[2020-01-21T18:59:27Z ERROR winit::platform::platform] X11 error: XError {
    description: "BadValue (integer parameter out of range for operation)",
    error_code: 2,
    request_code: 154,
    minor_code: 16,
}
[2020-01-21T18:59:27Z ERROR canvas::canvas_data] Unimplemented canvas2d.fillText. Values received: 51 MS (25-253), 3, 2, None.
[2020-01-21T18:59:27Z ERROR canvas::canvas_data] Unimplemented canvas2d.fillText. Values received: 15 MS (15-253), 3, 2, None.
   0: servo::backtrace::print
   1: servo::main::{{closure}}
   2: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:475
   3: rust_begin_unwind
             at src/libstd/panicking.rs:375
   4: core::panicking::panic_fmt
             at src/libcore/panicking.rs:84
   5: core::result::unwrap_failed
             at src/libcore/result.rs:1188
   6: winit::platform::platform::x11::EventsLoopProxy::wakeup
   7: <servo::events_loop::HeadedEventLoopWaker as webxr_api::registry::MainThreadWaker>::wake
   8: compositing::compositor_thread::CompositorProxy::send
   9: compositing::compositor_thread::CompositorProxy::recomposite
  10: webrender::render_backend::RenderBackend::update_document
  11: webrender::render_backend::RenderBackend::run
  12: std::sys_common::backtrace::__rust_begin_short_backtrace
  13: _ZN3std9panicking3try7do_call17he3101e9f26ca7365E.llvm.369990098206029157
  14: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:78
  15: core::ops::function::FnOnce::call_once{{vtable.shim}}
  16: <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once
             at /rustc/9b98af84c4aa66392236fff59c86da2130d46d46/src/liballoc/boxed.rs:1022
  17: <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once
             at /rustc/9b98af84c4aa66392236fff59c86da2130d46d46/src/liballoc/boxed.rs:1022
      std::sys_common::thread::start_thread
             at src/libstd/sys_common/thread.rs:13
      std::sys::unix::thread::Thread::new::thread_start
             at src/libstd/sys/unix/thread.rs:80
  18: start_thread
  19: __clone

[2020-01-21T18:59:27Z ERROR servo] Failed to call XSendEvent after wakeup: XError { description: "BadValue (integer parameter out of range for operation)", error_code: 2, request_code: 154, minor_code: 16 }
Stack trace for thread "WRRenderBackend#0"
stack backtrace:
   0: servo::backtrace::print
   1: servo::install_crash_handler::handler
   2: _ZL15WasmTrapHandleriP9siginfo_tPv
             at /home/manishearth/.cargo/git/checkouts/mozjs-fa11ffc7d4f1cc2d/5906588/mozjs/js/src/wasm/WasmSignalHandlers.cpp:969
   3: <unknown>
   4: core::ptr::real_drop_in_place
   5: webrender::render_backend::RenderBackend::run
   6: <unknown>

Servo exited with return value 11