From nobody Sun Apr 19 18:50:06 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B72DCCCA486 for ; Tue, 28 Jun 2022 06:27:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245500AbiF1G1P (ORCPT ); Tue, 28 Jun 2022 02:27:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234982AbiF1G1M (ORCPT ); Tue, 28 Jun 2022 02:27:12 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D8672316E for ; Mon, 27 Jun 2022 23:27:11 -0700 (PDT) Received: from dggpeml500023.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4LXF3n4sDFz9stm; Tue, 28 Jun 2022 14:26:29 +0800 (CST) Received: from dggpeml500003.china.huawei.com (7.185.36.200) by dggpeml500023.china.huawei.com (7.185.36.114) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 28 Jun 2022 14:27:09 +0800 Received: from huawei.com (10.175.103.91) by dggpeml500003.china.huawei.com (7.185.36.200) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 28 Jun 2022 14:27:08 +0800 From: Yu Liao To: , , , CC: , , Subject: [PATCH] drm/vc4: fix dereference before NULL check Date: Tue, 28 Jun 2022 14:36:57 +0800 Message-ID: <20220628063657.3169049-1-liaoyu15@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.103.91] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpeml500003.china.huawei.com (7.185.36.200) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The "perfmon" pointer is equal to the return value of idr_find which may be NULL, access by vc4_perfmon_get before checking if it was NULL. Fix this by dereferencing "perfmon" after "perfmon" has been null checked. Addresses-Coverity: ("Dereference before null check") Fixes: 65101d8c9108 ("drm/vc4: Expose performance counters to userspace") Signed-off-by: Yu Liao Reviewed-by: Boris Brezillon --- drivers/gpu/drm/vc4/vc4_perfmon.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/vc4/vc4_perfmon.c b/drivers/gpu/drm/vc4/vc4_pe= rfmon.c index c7f5adb6bcf8..ca969b8c7dde 100644 --- a/drivers/gpu/drm/vc4/vc4_perfmon.c +++ b/drivers/gpu/drm/vc4/vc4_perfmon.c @@ -17,13 +17,17 @@ =20 void vc4_perfmon_get(struct vc4_perfmon *perfmon) { - struct vc4_dev *vc4 =3D perfmon->dev; + struct vc4_dev *vc4; + + if (!perfmon) + return; + + vc4 =3D perfmon->dev; =20 if (WARN_ON_ONCE(vc4->is_vc5)) return; =20 - if (perfmon) - refcount_inc(&perfmon->refcnt); + refcount_inc(&perfmon->refcnt); } =20 void vc4_perfmon_put(struct vc4_perfmon *perfmon) --=20 2.25.1