From nobody Thu Dec 18 14:46:01 2025 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 205BEC4332F for ; Wed, 13 Dec 2023 11:44:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377778AbjLMLoc (ORCPT ); Wed, 13 Dec 2023 06:44:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233322AbjLMLoa (ORCPT ); Wed, 13 Dec 2023 06:44:30 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B8F6B0 for ; Wed, 13 Dec 2023 03:44:35 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CBDFC433C8; Wed, 13 Dec 2023 11:44:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702467875; bh=oMDLJR3QBu07Cmnnq8dPH187k2LYJ/Bh349mE/bY8oU=; h=From:To:Cc:Subject:Date:From; b=tQ1KpGhfjZNcUkxXi79TUZ0HBW1XEb69pN0LbOt68daPRWvfpzekQO7E2ChmRGle2 biouldnHtCuf7fbc3D7CGX8xnzjCNyVqXM5mxEFveKEuBo1xGfVQSLRhLM+q3N/pfe P+H9Z3RCadbQrOKYIOPXwR9sY+UZbxxXqX7OkXoBQROxFhtXgXsPxVCNWshjb7adO1 juZzy87gFjjUjxj7i1rLKg8da1JZZsn8sbBCHpUOVLItErdcomdop5XSD4YHl1av3D g1XduEVGHMzDJcOhR6klpIknCaAS/L6ebS4g8Rq5a9+h1aAvP9E+a0dfwFiI/8OnVA 3/WJK1RrTqE7A== From: Naveen N Rao To: , Cc: Steven Rostedt , Masami Hiramatsu , Shuah Khan , Michael Ellerman Subject: [PATCH v2] selftests/ftrace: Add test to exercize function tracer across cpu hotplug Date: Wed, 13 Dec 2023 17:08:02 +0530 Message-ID: <20231213113802.1278600-1-naveen@kernel.org> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add a test to exercize cpu hotplug with the function tracer active to ensure that sensitive functions in idle path are excluded from being traced. This helps catch issues such as the one fixed by commit 4b3338aaa74d ("powerpc/ftrace: Fix stack teardown in ftrace_no_trace"). Signed-off-by: Naveen N Rao Acked-by: Masami Hiramatsu (Google) --- v2: Add a check for next available online cpu, as suggested by Masami. .../ftrace/test.d/ftrace/func_hotplug.tc | 42 +++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/func_hotpl= ug.tc diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc b= /tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc new file mode 100644 index 000000000000..ccfbfde3d942 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc @@ -0,0 +1,42 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later +# description: ftrace - function trace across cpu hotplug +# requires: function:tracer + +if ! which nproc ; then + nproc() { + ls -d /sys/devices/system/cpu/cpu[0-9]* | wc -l + } +fi + +NP=3D`nproc` + +if [ $NP -eq 1 ] ;then + echo "We cannot test cpu hotplug in UP environment" + exit_unresolved +fi + +# Find online cpu +for i in /sys/devices/system/cpu/cpu[1-9]*; do + if [ -f $i/online ] && [ "$(cat $i/online)" =3D "1" ]; then + cpu=3D$i + break + fi +done + +if [ -z "$cpu" ]; then + echo "We cannot test cpu hotplug with a single cpu online" + exit_unresolved +fi + +echo 0 > tracing_on +echo > trace + +: "Set $(basename $cpu) offline/online with function tracer enabled" +echo function > current_tracer +echo 1 > tracing_on +(echo 0 > $cpu/online) +(echo "forked"; sleep 1) +(echo 1 > $cpu/online) +echo 0 > tracing_on +echo nop > current_tracer base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86 --=20 2.43.0