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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 A84E7C43461 for ; Thu, 10 Sep 2020 02:40:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 760B020770 for ; Thu, 10 Sep 2020 02:40:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730783AbgIJCkb (ORCPT ); Wed, 9 Sep 2020 22:40:31 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:46288 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730680AbgIJCic (ORCPT ); Wed, 9 Sep 2020 22:38:32 -0400 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 1487A9E9BBC2C9955179; Thu, 10 Sep 2020 10:38:21 +0800 (CST) Received: from localhost.localdomain.localdomain (10.175.113.25) by DGGEMS408-HUB.china.huawei.com (10.3.19.208) with Microsoft SMTP Server id 14.3.487.0; Thu, 10 Sep 2020 10:38:13 +0800 From: Jing Xiangfeng To: , , , , , , CC: , , Subject: [PATCH] drm/mm: prevent a potential null-pointer dereference Date: Thu, 10 Sep 2020 10:38:58 +0800 Message-ID: <20200910023858.43759-1-jingxiangfeng@huawei.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.113.25] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The macro 'DECLARE_NEXT_HOLE_ADDR' may hit a potential null-pointer dereference. So use 'entry' after checking it. Fixes: 5fad79fd66ff ("drm/mm: cleanup and improve next_hole_*_addr()") Signed-off-by: Jing Xiangfeng --- drivers/gpu/drm/drm_mm.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index a4a04d246135..6fcf70f71962 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -392,11 +392,14 @@ first_hole(struct drm_mm *mm, #define DECLARE_NEXT_HOLE_ADDR(name, first, last) \ static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \ { \ - struct rb_node *parent, *node = &entry->rb_hole_addr; \ + struct rb_node *parent, *node; \ \ - if (!entry || RB_EMPTY_NODE(node)) \ + if (!entry) \ return NULL; \ \ + node = &entry->rb_hole_addr; \ + if (RB_EMPTY_NODE(node)) \ + return NULL; \ if (usable_hole_addr(node->first, size)) { \ node = node->first; \ while (usable_hole_addr(node->last, size)) \ -- 2.17.1