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 F1B15ECAAA1 for ; Fri, 28 Oct 2022 07:30:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230138AbiJ1HaO (ORCPT ); Fri, 28 Oct 2022 03:30:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230131AbiJ1HaJ (ORCPT ); Fri, 28 Oct 2022 03:30:09 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C44F3CBDD for ; Fri, 28 Oct 2022 00:30:05 -0700 (PDT) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 29S7E3xa019527; Fri, 28 Oct 2022 07:30:01 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : subject : to : cc : references : in-reply-to : mime-version : message-id : content-type : content-transfer-encoding; s=pp1; bh=22ojzaejfatY0Mc3HvchrNvV8i8OCtp6rk/DAp/CDZU=; b=dmUbiYFutQrUplth8lgKLESBik4UjTG+a/aqjBi13wvdQId4f2GYmZxVQMnTLf1FWTBg qV+zwmnpzR52UhPYnGHYQCJ1DJz6QqCavRu/MgayoqsqdbfDkwQ07A5cuEBjEFRrBLa3 MFYRmDWaC/EQuy5Otir08kuy3QJkeKDINJWQU61PfnhLCvXjrpB8B8Wb/1ZYG0pYVF5u MqqcLmNcRKRtDjU64W6nlkYkRTbNVpN3bpkTHZ0/NXWR1uewqrl+TZ+z/4fVTyAWS9FJ +Q62Enf8OJbq3uPUAJze1BFS6qgILRhDPx3JEgKMeGNkRt5pnwWWwteR6/Lxv7Cg9BUl Tw== Received: from ppma04ams.nl.ibm.com (63.31.33a9.ip4.static.sl-reverse.com [169.51.49.99]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3kgagvre8b-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 28 Oct 2022 07:30:01 +0000 Received: from pps.filterd (ppma04ams.nl.ibm.com [127.0.0.1]) by ppma04ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 29S7KJ12009913; Fri, 28 Oct 2022 07:29:59 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma04ams.nl.ibm.com with ESMTP id 3kftf1sa2d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 28 Oct 2022 07:29:59 +0000 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 29S7TvaV34734708 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 28 Oct 2022 07:29:57 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 161CC42041; Fri, 28 Oct 2022 07:29:57 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EAE274203F; Fri, 28 Oct 2022 07:29:55 +0000 (GMT) Received: from localhost (unknown [9.43.57.156]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 28 Oct 2022 07:29:55 +0000 (GMT) Date: Fri, 28 Oct 2022 12:59:54 +0530 From: "Naveen N. Rao" Subject: Re: [PATCH] selftests/ftrace: Limit number of lines processed in 'trace' To: Masami Hiramatsu Cc: Akanksha J N , linux-kernel@vger.kernel.org, Steven Rostedt , Shuah Khan References: <20221017105502.307506-1-naveen.n.rao@linux.vnet.ibm.com> <20221017105103.540a87c7@gandalf.local.home> <20221019001949.950fb044677f96c6cdd00fdf@kernel.org> <20221018112224.372a3484@gandalf.local.home> <1666172148.1jppmgndx2.naveen@linux.ibm.com> <20221020004607.a78c771e12ad0f65c018220b@kernel.org> In-Reply-To: <20221020004607.a78c771e12ad0f65c018220b@kernel.org> MIME-Version: 1.0 User-Agent: astroid/4d6b06ad (https://github.com/astroidmail/astroid) Message-Id: <1666941493.vogf5bjzvv.naveen@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-GUID: SbjuqP9yl8gKxTefSPWO9UAPYSQ2KAtG X-Proofpoint-ORIG-GUID: SbjuqP9yl8gKxTefSPWO9UAPYSQ2KAtG X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-10-28_03,2022-10-27_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 impostorscore=0 lowpriorityscore=0 mlxscore=0 priorityscore=1501 malwarescore=0 adultscore=0 mlxlogscore=999 phishscore=0 suspectscore=0 spamscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2210170000 definitions=main-2210280044 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Masami Hiramatsu wrote: > On Wed, 19 Oct 2022 15:15:09 +0530 > "Naveen N. Rao" wrote: >=20 >> Steven Rostedt wrote: >> > On Wed, 19 Oct 2022 00:19:49 +0900 >> > Masami Hiramatsu (Google) wrote: >> >=20 >> >> > You need to make sure that the "pause-on-trace" option is set or tr= acing_on >> >> > is set to 0 (disabled). Otherwise, if the tracing is still active, = then the >> >> > reading of the trace file could potentially never end. =20 >> >>=20 >> >> initialize_ftrace() does this setting. So it must be set. >> >> If you run the ftracetest on old kernel, this feature is not there an= d >> >> it may cause a trouble. Naveen, can you clarify it? >>=20 >> Yes, the change to not pause on opening the trace file looks to be the=20 >> problem. >>=20 >> >=20 >> > 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 t= o not >> > pause the trace while reading it. >>=20 >> It looks like the kernel patch was picked up, but Masami's patch for the= =20 >> selftest wasn't backported. I have requested a test with that applied. >=20 > Good! That should be backported too. > BTW, which kernel version do you test? This was reported in internal tests with RHEL kernel. >=20 >>=20 >> Separately, before I saw your response, I came up with the below patch=20 >> to update the selftests to disable tracing before reading the trace=20 >> file. I have also requested this to be tested. >=20 > Yeah, OK. This also looks OK to me. This patch doesn't seem to be enough - event/subsystem-enable.tc also=20 needs updates. In light of that, I'm not sure if the large number of=20 disable_tracing statements required makes sense. So, I'm inclined to=20 drop this patch in favour of the existing pause-on-trace option. Thanks, Naveen