From patchwork Wed Feb 3 03:09:00 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 61054 Delivered-To: patch@linaro.org Received: by 10.112.43.199 with SMTP id y7csp50060lbl; Tue, 2 Feb 2016 19:09:36 -0800 (PST) X-Received: by 10.66.142.201 with SMTP id ry9mr52923042pab.89.1454468976447; Tue, 02 Feb 2016 19:09:36 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id cw6si5476970pad.86.2016.02.02.19.09.36; Tue, 02 Feb 2016 19:09:36 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932900AbcBCDJe (ORCPT + 30 others); Tue, 2 Feb 2016 22:09:34 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:45364 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932704AbcBCDJc (ORCPT ); Tue, 2 Feb 2016 22:09:32 -0500 Received: from 172.24.1.47 (EHLO szxeml433-hub.china.huawei.com) ([172.24.1.47]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id BVP34540; Wed, 03 Feb 2016 11:09:16 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by szxeml433-hub.china.huawei.com (10.82.67.210) with Microsoft SMTP Server id 14.3.235.1; Wed, 3 Feb 2016 11:09:05 +0800 From: Wang Nan To: CC: , Wang Nan , "Adrian Hunter" , Arnaldo Carvalho de Melo , Cody P Schafer , He Kuang , Jiri Olsa , Kirill Smelkov , Masami Hiramatsu , Namhyung Kim , Li Zefan , Subject: [PATCH v2 2/2] perf tools: Adjust symbol for shared objects Date: Wed, 3 Feb 2016 03:09:00 +0000 Message-ID: <1454468940-29981-3-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1454468940-29981-1-git-send-email-wangnan0@huawei.com> References: <1454468940-29981-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.56B16F5D.001F, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: ceabb7585eef827b9c71c5c2e0c19f0f Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org He Kuang reported a problem that perf fails to get correct symbol on Android platform in [1]. The problem can be reproduced on normal x86_64 platform. I will describe the reproducing steps in detail at the end of commit message. The reason of this problem is the missing of symbol adjustment for normal shared objects. In most of the cases it works correctly, but when '.text' section have different 'address' and 'offset' the result is wrong. I checked all shared objects in my working platform, only wine dll objects and debug objects (in .debug) have this problem. However, it is common on Android. For example: $ readelf -S ./libsurfaceflinger.so | grep \.text [10] .text PROGBITS 0000000000029030 00012030 This patch enables symbol adjustment for dynamic objects so the symbol address got from elfutils would be adjusted correctly. Now nearly all type of ELF file should adjust symbols. Makes ss->adjust_symbols default to true. Steps to reproduce the problem: $ cat ./Makefile PWD := $(shell pwd) LDFLAGS += "-Wl,-rpath=$(PWD)" CFLAGS += -g main: main.c libbuggy.so libbuggy.so: buggy.c gcc -g -shared -fPIC -Wl,-Ttext-segment=0x200000 $< -o $@ clean: rm -rf main libbuggy.so *.o $ cat ./buggy.c int fib(int x) { return (x == 0) ? 1 : (x == 1) ? 1 : fib(x - 1) + fib(x - 2); } $ cat ./main.c #include extern int fib(int x); int main() { int i; for (i = 0; i < 40; i++) printf("%d\n", fib(i)); return 0; } $ make $ perf record ./main ... $ perf report --stdio # Overhead Command Shared Object Symbol # ........ ....... ................. ............................... # 14.97% main libbuggy.so [.] 0x000000000000066c 8.68% main libbuggy.so [.] 0x00000000000006aa 8.52% main libbuggy.so [.] fib@plt 7.95% main libbuggy.so [.] 0x0000000000000664 5.94% main libbuggy.so [.] 0x00000000000006a9 5.35% main libbuggy.so [.] 0x0000000000000678 ... The correct result should be (after this patch): # Overhead Command Shared Object Symbol # ........ ....... ................. ............................... # 91.47% main libbuggy.so [.] fib 8.52% main libbuggy.so [.] fib@plt 0.00% main [kernel.kallsyms] [k] kmem_cache_free [1] http://lkml.kernel.org/g/1452567507-54013-1-git-send-email-hekuang@huawei.com Signed-off-by: Wang Nan Cc: Adrian Hunter Cc: Arnaldo Carvalho de Melo Cc: Cody P Schafer Cc: He Kuang Cc: Jiri Olsa Cc: Kirill Smelkov Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Li Zefan Cc: pi3orama@163.com --- tools/perf/util/symbol-elf.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) -- 1.8.3.4 diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 5227186..6a9a53a 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -708,17 +708,10 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, if (ss->opdshdr.sh_type != SHT_PROGBITS) ss->opdsec = NULL; - if (dso->kernel == DSO_TYPE_USER) { - GElf_Shdr shdr; - ss->adjust_symbols = (ehdr.e_type == ET_EXEC || - ehdr.e_type == ET_REL || - dso__is_vdso(dso) || - elf_section_by_name(elf, &ehdr, &shdr, - ".gnu.prelink_undo", - NULL) != NULL); - } else { + if (dso->kernel == DSO_TYPE_USER) + ss->adjust_symbols = true; + else ss->adjust_symbols = elf__needs_adjust_symbols(ehdr); - } ss->name = strdup(name); if (!ss->name) {