From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD8A1C4332F for ; Tue, 18 Oct 2022 15:22:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230034AbiJRPWe (ORCPT ); Tue, 18 Oct 2022 11:22:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230075AbiJRPWb (ORCPT ); Tue, 18 Oct 2022 11:22:31 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FC09D01AA for ; Tue, 18 Oct 2022 08:22:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B5EBE615CE for ; Tue, 18 Oct 2022 15:22:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78834C433C1; Tue, 18 Oct 2022 15:22:23 +0000 (UTC) Date: Tue, 18 Oct 2022 11:22:24 -0400 From: Steven Rostedt To: "Masami Hiramatsu (Google)" Cc: "Naveen N. Rao" , Shuah Khan , , Akanksha J N Subject: Re: [PATCH] selftests/ftrace: Limit number of lines processed in 'trace' Message-ID: <20221018112224.372a3484@gandalf.local.home> In-Reply-To: <20221019001949.950fb044677f96c6cdd00fdf@kernel.org> References: <20221017105502.307506-1-naveen.n.rao@linux.vnet.ibm.com> <20221017105103.540a87c7@gandalf.local.home> <20221019001949.950fb044677f96c6cdd00fdf@kernel.org> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 19 Oct 2022 00:19:49 +0900 Masami Hiramatsu (Google) wrote: > > You need to make sure that the "pause-on-trace" option is set or tracing_on > > is set to 0 (disabled). Otherwise, if the tracing is still active, then the > > reading of the trace file could potentially never end. > > initialize_ftrace() does this setting. So it must be set. > If you run the ftracetest on old kernel, this feature is not there and > it may cause a trouble. Naveen, can you clarify it? But for old kernels that do not have "pause-on-trace" it should be the default. The "pause-on-trace" was added when the default was changed to not pause the trace while reading it. -- Steve