From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753527AbdFVREV (ORCPT ); Thu, 22 Jun 2017 13:04:21 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:60594 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751598AbdFVRER (ORCPT ); Thu, 22 Jun 2017 13:04:17 -0400 Date: Thu, 22 Jun 2017 22:33:25 +0530 From: "Naveen N. Rao" To: Masami Hiramatsu Cc: Steven Rostedt , Ananth N Mavinakayanahalli , Michael Ellerman , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 2/2] selftests/ftrace: Update multiple kprobes test for powerpc References: <20170622180738.e97092d4fa6458b9199a03d7@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170622180738.e97092d4fa6458b9199a03d7@kernel.org> User-Agent: NeoMutt/20170609 (1.8.3) X-TM-AS-MML: disable x-cbid: 17062217-0040-0000-0000-00000333999E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17062217-0041-0000-0000-00000CAE4157 Message-Id: <20170622170325.qznheui7eydkdnmv@naverao1-tp.localdomain> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-06-22_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1706220293 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017/06/22 06:07PM, Masami Hiramatsu wrote: > On Thu, 22 Jun 2017 00:20:28 +0530 > "Naveen N. Rao" wrote: > > > KPROBES_ON_FTRACE is only available on powerpc64le. Update comment to > > clarify this. > > > > Also, we should use an offset of 8 to ensure that the probe does not > > fall on ftrace location. The current offset of 4 will fall before the > > function local entry point and won't fire, while an offset of 12 or 16 > > will fall on ftrace location. Offset 8 is currently guaranteed to not be > > the ftrace location. > > OK, these part seems good to me. > > > > > Finally, do not filter out symbols with a dot. Powerpc Elfv1 uses dot > > prefix for all functions and this prevents us from testing some of those > > symbols. Furthermore, with the patch to derive event names properly in > > the presence of ':' and '.', such names are accepted by kprobe_events > > and constitutes a good test for those symbols. > > Hmm, the reason why I added such filter was to avoid symbols including > gcc-generated suffixes like as .constprop or .isra etc. I see. I do wonder -- is there a problem if we try probing those symbols? On my local x86 vm, I don't see an issue probing it especially with the previous patch to enable probing with symbols having a '.' or ':'. Furthermore, since this is for testing kprobe_events, I feel it is good to try probing those symbols too to catch any weird errors we may hit. Thanks for the review! - Naveen > So if the Powerpc Elfv1 use dot prefix, that is OK, in that case, > could you update the filter as "^.*\\..*" ? > > Thank you, > > > > > Signed-off-by: Naveen N. Rao > > --- > > tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc > > index f4d1ff785d67..d209c071b2c0 100644 > > --- a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc > > +++ b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc > > @@ -2,16 +2,16 @@ > > # description: Register/unregister many kprobe events > > > > # ftrace fentry skip size depends on the machine architecture. > > -# Currently HAVE_KPROBES_ON_FTRACE defined on x86 and powerpc > > +# Currently HAVE_KPROBES_ON_FTRACE defined on x86 and powerpc64le > > case `uname -m` in > > x86_64|i[3456]86) OFFS=5;; > > - ppc*) OFFS=4;; > > + ppc64le) OFFS=8;; > > *) OFFS=0;; > > esac > > > > echo "Setup up to 256 kprobes" > > -grep t /proc/kallsyms | cut -f3 -d" " | grep -v .*\\..* | \ > > -head -n 256 | while read i; do echo p ${i}+${OFFS} ; done > kprobe_events ||: > > +grep t /proc/kallsyms | cut -f3 -d" " | head -n 256 | \ > > +while read i; do echo p ${i}+${OFFS} ; done > kprobe_events ||: > > > > echo 1 > events/kprobes/enable > > echo 0 > events/kprobes/enable > > -- > > 2.13.1 > > > > > -- > Masami Hiramatsu >