From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753183AbcFGDzK (ORCPT ); Mon, 6 Jun 2016 23:55:10 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:44431 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751399AbcFGDzI (ORCPT ); Mon, 6 Jun 2016 23:55:08 -0400 From: Wang Nan To: , CC: , , , Wang Nan , Arnaldo Carvalho de Melo Subject: [PATCH] perf tools: Fix crash in build_id_cache__kallsyms_path() Date: Tue, 7 Jun 2016 03:54:38 +0000 Message-ID: <1465271678-7392-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.57564591.0040,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 532d07c66f157a0653204ee0fb0801b3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org build_id_cache__kallsyms_path() accept string buffer but also alloc buffer by itself using asnprintf. Unfortunately, the only user of it passes it a stack-allocated buffer. Freeing it causes crash like this: $ perf script *** Error in `/home/wangnan/perf': free(): invalid pointer: 0x00007fffffff9630 *** ======= Backtrace: ========= lib64/libc.so.6(+0x6eeef)[0x7ffff5dbaeef] lib64/libc.so.6(+0x78cae)[0x7ffff5dc4cae] lib64/libc.so.6(+0x79987)[0x7ffff5dc5987] /home/w00229757/perf(build_id_cache__kallsyms_path+0x6b)[0x49681b] /home/w00229757/perf[0x4bdd40] /home/w00229757/perf(dso__load+0xa3a)[0x4c048a] /home/w00229757/perf(map__load+0x6f)[0x4d561f] /home/w00229757/perf(thread__find_addr_map+0x235)[0x49e935] /home/w00229757/perf(machine__resolve+0x7d)[0x49ec6d] /home/w00229757/perf[0x4555a8] /home/w00229757/perf[0x4d9507] /home/w00229757/perf[0x4d9e80] /home/w00229757/perf(ordered_events__flush+0x354)[0x4dd444] /home/w00229757/perf(perf_session__process_events+0x3d0)[0x4dc140] /home/w00229757/perf(cmd_script+0x12b0)[0x4592e0] /home/w00229757/perf[0x4911f1] /home/w00229757/perf(main+0x68f)[0x4352ef] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7ffff5d6dbd5] /home/w00229757/perf[0x435415] ======= Memory map: ======== This patch simplify build_id_cache__kallsyms_path(), don't even consider allocate string buffer, so never free anything. The caller of it should management memory allocation. Signed-off-by: Wang Nan Cc: Masami Hiramatsu Cc: Arnaldo Carvalho de Melo Fixes: 01412261d994 ("perf buildid-cache: Use path/to/bin/buildid/elf instead of path/to/bin/buildid") --- tools/perf/util/build-id.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c index 67f986c..20aef90 100644 --- a/tools/perf/util/build-id.c +++ b/tools/perf/util/build-id.c @@ -147,20 +147,17 @@ static int asnprintf(char **strp, size_t size, const char *fmt, ...) char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf, size_t size) { - bool is_alloc = !!bf; bool retry_old = true; - asnprintf(&bf, size, "%s/%s/%s/kallsyms", - buildid_dir, DSO__NAME_KALLSYMS, sbuild_id); + snprintf(bf, size, "%s/%s/%s/kallsyms", + buildid_dir, DSO__NAME_KALLSYMS, sbuild_id); retry: if (!access(bf, F_OK)) return bf; - if (is_alloc) - free(bf); if (retry_old) { /* Try old style kallsyms cache */ - asnprintf(&bf, size, "%s/%s/%s", - buildid_dir, DSO__NAME_KALLSYMS, sbuild_id); + snprintf(bf, size, "%s/%s/%s", + buildid_dir, DSO__NAME_KALLSYMS, sbuild_id); retry_old = false; goto retry; } -- 1.8.3.4