From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752160AbcGSDfX (ORCPT ); Mon, 18 Jul 2016 23:35:23 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:56587 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751244AbcGSDfU (ORCPT ); Mon, 18 Jul 2016 23:35:20 -0400 X-IBM-Helo: d03dlp01.boulder.ibm.com X-IBM-MailFrom: gongss@linux.vnet.ibm.com Subject: Re: [RFC PATCH V2] s390/perf: fix 'start' address of module's map To: Jiri Olsa References: <1468577711-6622-1-git-send-email-gongss@linux.vnet.ibm.com> <1468577711-6622-2-git-send-email-gongss@linux.vnet.ibm.com> <20160718140754.GA9555@krava> <36b58f7b-e0c5-ee35-e154-c6b711817666@linux.vnet.ibm.com> Cc: acme@kernel.org, jolsa@kernel.org, dsahern@gmail.com, linux-kernel@vger.kernel.org, borntraeger@de.ibm.com From: Songshan Gong Date: Tue, 19 Jul 2016 11:35:13 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <36b58f7b-e0c5-ee35-e154-c6b711817666@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16071903-0004-0000-0000-00000FEFF910 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16071903-0005-0000-0000-000077322EB7 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-07-18_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1607190039 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 7/19/2016 9:50 AM, Songshan Gong 写道: > > > 在 7/19/2016 9:37 AM, Songshan Gong 写道: >> >> >> 在 7/18/2016 10:07 PM, Jiri Olsa 写道: >>> On Fri, Jul 15, 2016 at 06:15:11PM +0800, Song Shan Gong wrote: >>>> At preset, when creating module's map, perf gets 'start' address by >>>> parsing >>>> '/proc/modules', but it's module base address, isn't the start >>>> address of >>>> '.text' section. In most archs, it's OK. But for s390, it places >>>> 'GOT' and >>>> 'PLT' relocations before '.text' section. So there exists an offset >>>> between >>>> module base address and '.text' section, which will incur wrong symbol >>>> resolution for modules. >>>> >>>> Fix this bug by getting 'start' address of module's map from parsing >>>> '/sys/module/[module name]/sections/.text', not from '/proc/modules'. >>>> >>>> Signed-off-by: Song Shan Gong >>>> --- >>>> tools/perf/arch/s390/util/Build | 2 ++ >>>> tools/perf/arch/s390/util/sym-handling.c | 27 >>>> +++++++++++++++++++++++++++ >>>> tools/perf/util/machine.c | 8 ++++++++ >>>> tools/perf/util/machine.h | 1 + >>>> 4 files changed, 38 insertions(+) >>>> create mode 100644 tools/perf/arch/s390/util/sym-handling.c >>>> >>>> diff --git a/tools/perf/arch/s390/util/Build >>>> b/tools/perf/arch/s390/util/Build >>>> index 8a61372..5e322ed 100644 >>>> --- a/tools/perf/arch/s390/util/Build >>>> +++ b/tools/perf/arch/s390/util/Build >>>> @@ -2,3 +2,5 @@ libperf-y += header.o >>>> libperf-y += kvm-stat.o >>>> >>>> libperf-$(CONFIG_DWARF) += dwarf-regs.o >>>> + >>>> +libperf-y += sym-handling.o >>>> diff --git a/tools/perf/arch/s390/util/sym-handling.c >>>> b/tools/perf/arch/s390/util/sym-handling.c >>>> new file mode 100644 >>>> index 0000000..ff51336 >>>> --- /dev/null >>>> +++ b/tools/perf/arch/s390/util/sym-handling.c >>>> @@ -0,0 +1,27 @@ >>>> +#include >>>> +#include >>>> +#include >>>> +#include "util.h" >>>> +#include "machine.h" >>>> +#include "api/fs/fs.h" >>>> + >>>> +int arch__fix_module_text_start(u64 *start, const char *name) >>>> +{ >>>> + char path[PATH_MAX]; >>>> + char *module_name = NULL; >>>> + int len; >>>> + >>>> + if (!(module_name = strdup(name))) >>>> + return -1; >>>> + >>>> + len = strlen(module_name); >>>> + module_name[len - 1] = '\0'; >>>> + snprintf(path, PATH_MAX, "module/%s/sections/.text", >>>> + module_name + 1); >>> >>> why can't you use 'name' in here? I can't see the reason >>> you allocated module_name.. >> >> Oh, yes. >> > Sorry, just ignore the upper reply. > > I use the 'module_name' here instead of 'name', because 'name' is > something like '[module_name]', I need strip the '[' and ']', so I have > to set the tail ']' to '\0' to indicate the string end, which will need > change the constant variable 'name'. > eeee, I found a new way to implement it. I could use '%.*s' to format the 'path', 'name' is enough indeed. It's so concise now. Appreciate. > >> >>>> + >>>> + if (sysfs__read_ull(path, (unsigned long long *)start) < 0) { >>>> + free(module_name); >>>> + return -1; >>>> + } >>> >>> leaking module_name in here >> >> yes, thanks. >>> >>>> + return 0; >>>> +} >>> >>> SNIP >>> >>> thanks, >>> jirka >>> >> > -- SongShan Gong