Workaround for crash when rendering particle systems, don't draw objects with

particle systems in the 3d view while rendering, this will recompute the particles
in the modifier stack, while these are being manipulated by the render engine
at the same time... a better fix is needed clearly but quite difficult.

source/blender/editors/space_view3d/drawobject.c

@@ -5166,6 +5166,10 @@ void draw_object(Scene *scene, ARegion *ar, View3D *v3d, Base *base, int flag)
 			return;
 	}
 
+	/* XXX particles are not safe for simultaneous threaded render */
+	if(G.rendering && ob->particlesystem.first)
+		return;
+
 	/* xray delay? */
 	if((flag & DRAW_PICKING)==0 && (base->flag & OB_FROMDUPLI)==0) {
 		/* don't do xray in particle mode, need the z-buffer */