That is inappropriate use of arch details in generic code. It might happen to be harmless fritter in practice on the arch's we have but it is certainly not the correct way to go about things. You should just call user_disable_single_step() unconditionally. Even on an arch with no such machinery at all that should be defined safely as a no-op (see linux/ptrace.h). If there is some reason not to do that, please explain it. Thanks, Roland -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html