From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1427830AbcBSLvg (ORCPT ); Fri, 19 Feb 2016 06:51:36 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:17356 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946974AbcBSLve (ORCPT ); Fri, 19 Feb 2016 06:51:34 -0500 From: Wang Nan To: Alexei Starovoitov , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Brendan Gregg CC: Adrian Hunter , Cody P Schafer , "David S. Miller" , He Kuang , =?UTF-8?q?J=C3=A9r=C3=A9mie=20Galarneau?= , Jiri Olsa , Kirill Smelkov , Li Zefan , Masami Hiramatsu , Namhyung Kim , Peter Zijlstra , , Wang Nan , Subject: [PATCH 39/55] perf record: Prevent reading invalid data in record__mmap_read Date: Fri, 19 Feb 2016 11:44:27 +0000 Message-ID: <1455882283-79592-40-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1455882283-79592-1-git-send-email-wangnan0@huawei.com> References: <1455882283-79592-1-git-send-email-wangnan0@huawei.com> 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=0001.0A090205.56C7006A.0029,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: 4b83a6346e62c17dffb5bcf6b7493b03 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When record__mmap_read() requires data more than the size of ring buffer, drop those data to avoid accessing invalid memory. This can happen when reading from overwritable ring buffer, which should be avoided. However, check this for robustness. Signed-off-by: Wang Nan Signed-off-by: He Kuang Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com --- tools/perf/builtin-record.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 310e290..3a7de24 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -37,6 +37,7 @@ #include #include #include +#include struct record { @@ -95,6 +96,13 @@ static int record__mmap_read(struct record *rec, int idx) rec->samples++; size = head - old; + if (size > (unsigned long)(md->mask) + 1) { + WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n"); + + md->prev = head; + perf_evlist__mmap_consume(rec->evlist, idx); + return 0; + } if ((old & md->mask) + size != (head & md->mask)) { buf = &data[old & md->mask]; -- 1.8.3.4