From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752820AbcBZJd4 (ORCPT ); Fri, 26 Feb 2016 04:33:56 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:8971 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752596AbcBZJdt (ORCPT ); Fri, 26 Feb 2016 04:33:49 -0500 From: Wang Nan To: Alexei Starovoitov , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo CC: Jiri Olsa , Li Zefan , "Peter Zijlstra" , , Wang Nan , , He Kuang , Masami Hiramatsu , Namhyung Kim Subject: [PATCH 30/46] perf record: Prevent reading invalid data in record__mmap_read Date: Fri, 26 Feb 2016 09:32:18 +0000 Message-ID: <1456479154-136027-31-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1456479154-136027-1-git-send-email-wangnan0@huawei.com> References: <1456479154-136027-1-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=0001.0A090205.56D01BF2.002E,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: 9c653ecd2ffdf560a2510648e1fe64d9 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 fa16099..9ffdef9 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -38,6 +38,7 @@ #include #include #include +#include struct record { @@ -96,6 +97,13 @@ 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