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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 D06B8C10DCE for ; Fri, 13 Mar 2020 12:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7B4820746 for ; Fri, 13 Mar 2020 12:27:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Q6caX3YM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726761AbgCMM1g (ORCPT ); Fri, 13 Mar 2020 08:27:36 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:34278 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726395AbgCMM1g (ORCPT ); Fri, 13 Mar 2020 08:27:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=xY8EzI7X1E8hN1FOxDAVneZEH2bSUqBcmp3TlzBpd60=; b=Q6caX3YMsIwxNzme3u2/ZGuMq3 RJLpXujvtnUDTkaSroJgFk2QVA8lUuJWDmTO3s3yxRKcjWsKPaxE+WBb6Yg/FAJGwOV828RgEPMrh 6Ma85LFcQ0BsMRUhRTIifaq8JkNn30517a64DY2JFdw6EKO7qyI942X27rkNeC6TuYPqNa7fHBI0O 5j148hQn4meM2VQnlhZR7PocT+H8aIVrc/x0vFKWIfWO4Rzkp+fsqDRDxXUPiUYld+6b1uBNDpGy1 P5VI24mJknWoatprhr/3xzqamQrWJjvG0h0mpPE+8Ql0SNShnkxQgU6tav0OlI/4V4Kd6VtFE01mQ M4bixk/w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jCjPV-0004Oh-3N; Fri, 13 Mar 2020 12:27:29 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 34A8B3011E0; Fri, 13 Mar 2020 13:27:26 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id EC6F02BE01201; Fri, 13 Mar 2020 13:27:25 +0100 (CET) Date: Fri, 13 Mar 2020 13:27:25 +0100 From: Peter Zijlstra To: Dan Carpenter Cc: Ian Rogers , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] perf/core: Fix reversed NULL check in perf_event_groups_less() Message-ID: <20200313122725.GZ12561@hirez.programming.kicks-ass.net> References: <20200312105637.GA8960@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200312105637.GA8960@mwanda> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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! From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Date: Fri, 13 Mar 2020 12:27:25 +0000 Subject: Re: [PATCH] perf/core: Fix reversed NULL check in perf_event_groups_less() Message-Id: <20200313122725.GZ12561@hirez.programming.kicks-ass.net> List-Id: References: <20200312105637.GA8960@mwanda> In-Reply-To: <20200312105637.GA8960@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dan Carpenter Cc: Ian Rogers , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org 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!