From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28549C4332B for ; Sat, 21 Mar 2020 02:24:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC0732072C for ; Sat, 21 Mar 2020 02:24:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="hhhGA9UW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727891AbgCUCY4 (ORCPT ); Fri, 20 Mar 2020 22:24:56 -0400 Received: from mail-yb1-f193.google.com ([209.85.219.193]:41046 "EHLO mail-yb1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726851AbgCUCYz (ORCPT ); Fri, 20 Mar 2020 22:24:55 -0400 Received: by mail-yb1-f193.google.com with SMTP id d5so3559984ybs.8 for ; Fri, 20 Mar 2020 19:24:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=+sWKQj4Uyupgpe20upDE1CDsAGcVde2eq3FfcxBSqtw=; b=hhhGA9UWT/3U3ety3Si0Pz+2VxrteiTL1w2fW4bALSSesaU013GbJx65VYFnvA9xJi PHkjaaMIK1gC+VuQmx5FfVzqBzHHafuApDFLj/NgqQB+EoNfoNIzUgxtIkO1Mg1mloJ2 D/prA/1Ki/1Rb2avhc0bglsFnNcxG3gyjTL19zKhKI1/QZ8+Lqt6LoCMRNj4lhDXsSiC V72m7zm3JPzTDQ8cdjCEHc3Dac7+ANXd0DVY10LnduPwCBMiq7A6XWBA5DIn9ikouIdA jiKsmCS3x81Y8qJhMF2qdqc0zhxLcOZqh7IjVEorKM9fMXARKBDU1KGmMfiCmSJJzyDF eu2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=+sWKQj4Uyupgpe20upDE1CDsAGcVde2eq3FfcxBSqtw=; b=D0tvyjcyZ5AP1amyMwXsvIQvXveXf7IBnQFaFaCj29tIl7y/iM0djApfJ+0Yuw66LI cFej2kK6tqfhjmDefMlm9xvGq21joGpN2tY9v+Jr13JCIY3FWYJA/CzxF0EY88WDocvw v+ELfx1I+6gQ+FmWIhpWVP2gEFwrrAEtu9ePefRJt7lmmL6B9mK2qcAeimslMwbaQe9Q XApc05Nl7WF5pu8AcolZLjhAKhJIDWtGAlLF8iX4lwlhhgkEuvZJBMyWFl3Rw+WAZihy 6Vj070DIghuCIlJcxHxRAX9kzUqm3RrAZ2FVguxjpVZQ3OlrujqqfvFRntxmArYymGkQ j27g== X-Gm-Message-State: ANhLgQ2HIUxk88Wjzgel67mPbsDrt5SPKdUPzJz2erTqiuRsH3MGKaZ4 kDM3aCByVQkBD1e1BNe6FoLx/+EXdfFxfyHgU6Y6yA== X-Google-Smtp-Source: ADFU+vvpQCpgtKO5Wxl1XzXEkIWs1WgNh8zCu/SCP6QXwgMX5OdlFp1qeFH3leT5seMN72TsRh1BZFIidMBUuBQIMgA= X-Received: by 2002:a25:9787:: with SMTP id i7mr17042865ybo.383.1584757492441; Fri, 20 Mar 2020 19:24:52 -0700 (PDT) MIME-Version: 1.0 References: <20200312105637.GA8960@mwanda> <20200313122725.GZ12561@hirez.programming.kicks-ass.net> In-Reply-To: <20200313122725.GZ12561@hirez.programming.kicks-ass.net> From: Ian Rogers Date: Fri, 20 Mar 2020 19:24:41 -0700 Message-ID: Subject: Re: [PATCH] perf/core: Fix reversed NULL check in perf_event_groups_less() To: Peter Zijlstra Cc: Dan Carpenter , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , LKML , kernel-janitors@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 13, 2020 at 5:27 AM Peter Zijlstra wrote: > > On Thu, Mar 12, 2020 at 01:56:37PM +0300, Dan Carpenter wrote: > > This NULL check is reversed so it leads to a Smatch warning and > > presumably a NULL dereference. > > > > kernel/events/core.c:1598 perf_event_groups_less() > > error: we previously assumed 'right->cgrp->css.cgroup' could be null > > (see line 1590) > > > > Fixes: 95ed6c707f26 ("perf/cgroup: Order events in RB tree by cgroup id") > > Signed-off-by: Dan Carpenter > > --- > > kernel/events/core.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > index 6a47c3e54fe9..607c04ec7cfa 100644 > > --- a/kernel/events/core.c > > +++ b/kernel/events/core.c > > @@ -1587,7 +1587,7 @@ perf_event_groups_less(struct perf_event *left, struct perf_event *right) > > */ > > return true; > > } > > - if (!right->cgrp || right->cgrp->css.cgroup) { > > + if (!right->cgrp || !right->cgrp->css.cgroup) { > > /* > > * Right has no cgroup but left does, no cgroups come > > * first. > > Thanks! Also much thanks! Ian From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Rogers Date: Sat, 21 Mar 2020 02:24:41 +0000 Subject: Re: [PATCH] perf/core: Fix reversed NULL check in perf_event_groups_less() Message-Id: List-Id: References: <20200312105637.GA8960@mwanda> <20200313122725.GZ12561@hirez.programming.kicks-ass.net> In-Reply-To: <20200313122725.GZ12561@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Peter Zijlstra Cc: Dan Carpenter , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , LKML , kernel-janitors@vger.kernel.org On Fri, Mar 13, 2020 at 5:27 AM Peter Zijlstra wrote: > > On Thu, Mar 12, 2020 at 01:56:37PM +0300, Dan Carpenter wrote: > > This NULL check is reversed so it leads to a Smatch warning and > > presumably a NULL dereference. > > > > kernel/events/core.c:1598 perf_event_groups_less() > > error: we previously assumed 'right->cgrp->css.cgroup' could be null > > (see line 1590) > > > > Fixes: 95ed6c707f26 ("perf/cgroup: Order events in RB tree by cgroup id") > > Signed-off-by: Dan Carpenter > > --- > > kernel/events/core.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > index 6a47c3e54fe9..607c04ec7cfa 100644 > > --- a/kernel/events/core.c > > +++ b/kernel/events/core.c > > @@ -1587,7 +1587,7 @@ perf_event_groups_less(struct perf_event *left, struct perf_event *right) > > */ > > return true; > > } > > - if (!right->cgrp || right->cgrp->css.cgroup) { > > + if (!right->cgrp || !right->cgrp->css.cgroup) { > > /* > > * Right has no cgroup but left does, no cgroups come > > * first. > > Thanks! Also much thanks! Ian