From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752477AbcGSBuy (ORCPT ); Mon, 18 Jul 2016 21:50:54 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:56166 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752187AbcGSBuw (ORCPT ); Mon, 18 Jul 2016 21:50:52 -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> 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 09:50:43 +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: 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: 16071901-8235-0000-0000-000008D08681 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16071901-8236-0000-0000-00003336E384 Message-Id: <36b58f7b-e0c5-ee35-e154-c6b711817666@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-07-18_09:,, 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-1607190019 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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'. > >>> + >>> + 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