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 798DDC4332F for ; Tue, 22 Nov 2022 02:34:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231261AbiKVCeL convert rfc822-to-8bit (ORCPT ); Mon, 21 Nov 2022 21:34:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230482AbiKVCeI (ORCPT ); Mon, 21 Nov 2022 21:34:08 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96AC1BF5BF for ; Mon, 21 Nov 2022 18:34:07 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id 2907BB81603 for ; Tue, 22 Nov 2022 02:34:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76A06C433C1; Tue, 22 Nov 2022 02:34:04 +0000 (UTC) Date: Mon, 21 Nov 2022 21:34:02 -0500 From: Steven Rostedt To: Song Shuai Cc: mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ftrace: avoid replacing the list func with itself Message-ID: <20221121213402.154adf09@rorschach.local.home> In-Reply-To: References: <20221026132039.2236233-1-suagrfillet@gmail.com> 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=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 22 Nov 2022 02:28:25 +0000 Song Shuai wrote: > Song Shuai 于2022年10月26日周三 13:20写道： > > > > The list func (ftrace_ops_list_func) will be patched first > > before the transition between old and new calls are set, > > which fixed the race described in this commit `59338f75`. > > > > While ftrace_trace_function changes from the list func to a > > ftrace_ops func, like unregistering the klp_ops to leave the only > > global_ops in ftrace_ops_list, the ftrace_[regs]_call will be > > replaced with the list func although it already exists. So there > > should be a condition to avoid this. > > > > This patch backups saved_ftrace_func by saved_ftrace_func_old > > which will be compared with the list func before trying to patch it. > > > Ping... Thanks for the ping. I had thought I had replied to this, but I don't see it in my sent folder. I may have been distracted, and lost the message. I'll take a look at it tomorrow. -- Steve