From patchwork Wed Dec 13 11:38:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 754116 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84C1B24B52 for ; Wed, 13 Dec 2023 11:44:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tQ1KpGhf" 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 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 --- 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_hotplug.tc base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86 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=`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 $i/online)" = "1" ]; then + cpu=$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