From patchwork Wed May 25 13:44:49 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 68605 Delivered-To: patch@linaro.org Received: by 10.140.92.199 with SMTP id b65csp1226818qge; Wed, 25 May 2016 06:51:37 -0700 (PDT) X-Received: by 10.66.41.43 with SMTP id c11mr5995151pal.96.1464184297844; Wed, 25 May 2016 06:51:37 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id j10si30064351pfa.161.2016.05.25.06.51.37; Wed, 25 May 2016 06:51:37 -0700 (PDT) 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 S1753979AbcEYNve (ORCPT + 30 others); Wed, 25 May 2016 09:51:34 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:37608 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751660AbcEYNvc (ORCPT ); Wed, 25 May 2016 09:51:32 -0400 Received: from 172.24.1.136 (EHLO szxeml433-hub.china.huawei.com) ([172.24.1.136]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id CCE84131; Wed, 25 May 2016 21:45:10 +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, 25 May 2016 21:45:02 +0800 From: Wang Nan To: CC: , , Wang Nan , He Kuang , "Arnaldo Carvalho de Melo" , Jiri Olsa , Masami Hiramatsu , Namhyung Kim , "Zefan Li" Subject: [PATCH v6 01/10] perf tools: Check 'base' pointer before checking refcnt when put a mmap Date: Wed, 25 May 2016 13:44:49 +0000 Message-ID: <1464183898-174512-2-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1464183898-174512-1-git-send-email-wangnan0@huawei.com> References: <1464183898-174512-1-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=0001.0A020204.5745AC66.0474, 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: 2ff94aa533e3787e90a8460978daab90 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org evlist->mmap[i]->refcnt could be 0 if an evlist has no evsel or all evsels don't match the evlist during mmap. For example, when all evsels are overwritable but the evlist itself is normal. To avoid crashing, perf should check 'base' pointer before checking refcnt, and raise bug only when base is not NULL. Signed-off-by: Wang Nan Cc: 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/util/evlist.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) -- 1.8.3.4 diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index fbd0d47..f916d25 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -857,9 +857,11 @@ static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx) static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx) { - BUG_ON(atomic_read(&evlist->mmap[idx].refcnt) == 0); + struct perf_mmap *mmap = &evlist->mmap[idx]; - if (atomic_dec_and_test(&evlist->mmap[idx].refcnt)) + BUG_ON(mmap->base && atomic_read(&mmap->refcnt) == 0); + + if (atomic_dec_and_test(&mmap->refcnt)) __perf_evlist__munmap(evlist, idx); }