From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752991AbcEWWDt (ORCPT ); Mon, 23 May 2016 18:03:49 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:55995 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752902AbcEWWDo (ORCPT ); Mon, 23 May 2016 18:03:44 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Wang Nan , Jiri Olsa , Masami Hiramatsu , Namhyung Kim , Zefan Li , pi3orama@163.com, He Kuang , Arnaldo Carvalho de Melo Subject: [PATCH 7/9] perf record: Prevent reading invalid data in record__mmap_read Date: Mon, 23 May 2016 19:03:26 -0300 Message-Id: <1464041008-4825-8-git-send-email-acme@kernel.org> X-Mailer: git-send-email 2.5.5 In-Reply-To: <1464041008-4825-1-git-send-email-acme@kernel.org> References: <1464041008-4825-1-git-send-email-acme@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wang Nan 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 Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1463987628-163563-3-git-send-email-wangnan0@huawei.com Signed-off-by: He Kuang Signed-off-by: Arnaldo Carvalho de Melo --- 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 f3679c44d3f3..f302cc937ca5 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -40,6 +40,7 @@ #include #include #include +#include struct record { @@ -98,6 +99,13 @@ 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]; -- 2.5.5