From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.web.de (mout.web.de [212.227.15.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F5209449 for ; Sat, 22 Jun 2024 14:27:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.227.15.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719066457; cv=none; b=EhUiVIOkgXZyVhGI1segLl5arM4/vdtO/T8KVrIDNCB7OJLf60Fo7nK3nd1WUqH6TP14EIscSAkmzW+1WKl5aOY68WvzCu0MZwnXzcpDND7J7pVIXtIJbKob1Hl25u6SNG6J0gTXITA/kK0rT44fhabhmUD4aFII/+La6NGumZ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719066457; c=relaxed/simple; bh=rT0MlomAF4vpJIl+TyQxKf214SZ5k/nVDmjl3wKHLm8=; h=Message-ID:Date:MIME-Version:To:Cc:References:Subject:From: In-Reply-To:Content-Type; b=YOI2LqdgBT5ckw3cqJSGdPxgw8ooOAsyYPgoV6TmaMErLIUvi78AXjPO+Tmm437sAwS8GlepwdhvnvBhCVgd3M/HPN7sgdvgKdMjobbsm7wgfgpBtbL2qFv4eTFzZxz2sdhBXufMxqNbDqvn6EQNPMSq508Sv6RsiFrJOAlhovM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=web.de; spf=pass smtp.mailfrom=web.de; dkim=pass (2048-bit key) header.d=web.de header.i=markus.elfring@web.de header.b=omYtq9hd; arc=none smtp.client-ip=212.227.15.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=web.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=web.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=web.de header.i=markus.elfring@web.de header.b="omYtq9hd" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=web.de; s=s29768273; t=1719066428; x=1719671228; i=markus.elfring@web.de; bh=OU3x5Yr/XJbHSekpCJjHsOQ0enVAT5S79Ev31+LNqlc=; h=X-UI-Sender-Class:Message-ID:Date:MIME-Version:To:Cc:References: Subject:From:In-Reply-To:Content-Type:Content-Transfer-Encoding: cc:content-transfer-encoding:content-type:date:from:message-id: mime-version:reply-to:subject:to; b=omYtq9hd4Du2D3dE0n391ig+RBOnSzAX1G6h2QdmCIyoIOdmYTJmuHsMmtaw75nU laIbmpDhvHCPn4xrb7uitoEKNlkGCpuWFaXV6PxjTqJMF+lHE60wlZ0GrsYMPlH+q SZQddArm1M6fxFBdEk1DBN57OHhdcogk/3p/vNRaOCW41l5gcJu0n15zfv7ocdyfH csU6rpciG8FUwddNCdEvJ4GTmAROFGxuOsT6LlxIsCTwN4dKRE6m2OV+i8RQLIGeI vip0uBu3E1zavbvkKJwTtIBETBbXrfakbbKhNZYFA2+5dofep76SDZwu9idMuBS42 kyYP/VYU8LJsAqvntg== X-UI-Sender-Class: 814a7b36-bfc1-4dae-8640-3722d8ec6cd6 Received: from [192.168.178.21] ([94.31.85.95]) by smtp.web.de (mrweb006 [213.165.67.108]) with ESMTPSA (Nemesis) id 1MdwNW-1ssQmY0mBS-00lnt8; Sat, 22 Jun 2024 16:27:08 +0200 Message-ID: <0032d02a-b5ae-452e-b26e-14dc7f091e6b@web.de> Date: Sat, 22 Jun 2024 16:26:58 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Ma Ke , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Alex Deucher , Aurabindo Pillai , Chen Jiahao , =?UTF-8?Q?Christian_K=C3=B6nig?= , Daniel Vetter , David Airlie , Guchun Chen , Srinivasan Shanmugam , Xinhui Pan Cc: LKML References: <20240622082219.1876200-1-make24@iscas.ac.cn> Subject: Re: [PATCH] drm/amdgpu: fix a possible null pointer dereference Content-Language: en-GB From: Markus Elfring In-Reply-To: <20240622082219.1876200-1-make24@iscas.ac.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:UEl50w9SKYfEiP4nvrpAPA/v1Qhr4FoGAsA/ycA54SOmxbzGd/H axwN+KFtDoIptrKRtu76J2DyX5IDAGzPlrG89mVteXjbymSd4zMntXERGDnV4agdj3ynHeL Wh0P1qvUAjv3fR3A6UMsfroWT60pkAR56evrkpxSvzRDNpQNxGMqcMuw5ixWPr0SS6+LLDh ymINEHB7UHz5sEgWogZ4w== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:mEgeRSeD7oM=;JwuzwH1XlfI/DqiThZ861vIU57u /Tw0ZE2FHOVYj0R2f0QNYFwqeXlQN3v71UfzBEAofL2QPnq8jERFdoAXwo1Z2/jn42NxhlU3d kRBmrjKsGfJ3mKPQBNO+v/iJ3c15JZ5/XqSIJ/3IW2906hRN0XaC+V9wF63vv/2ENonkWVCaL U372v3r6N7vbqKwpO+RZVUeLJQi040IRZePhxiR+rk+2/L84dzrNQHw4GtaXEitHIAUYe8XmZ MvJV/hLhSOEs8uTUWIQddAtW2NTu5NG6acIX7J0iJTpQM79faSEHI5ARGc2ofCXPIus5wPhhJ oTN4PalqGjfTlba66wU9Q6dMEmdpiSfo1WMmAoblYd3APgRsa2E4yMsF50YLrfnGZV7Cz5VUU 9N8E4K4vWSV0xoHySbp1t6HhtZ5sJaMehaPO5vu8heuRllhuIJr6nAgFHr5nHkUNPDBMMLo+n /pgc7rlzJMbGkc60w1YBLye+vEfmvFwFVdE+lD2VmcLsA7MUypnWOhYE5eVlhYn0cB/bNoXYP Sjt51mrG+fdJBlYpx47CyvOKiguSBSpuqeIo311LeGH+CXIQC9FpXW2Yimzre23IO3dqPFJyz 6ZzQ2PSZl3L1T+d57CYUo49w65PxeETN4qa8DXSviZTO7YCQsWaSBLMZuXClAGeskCbj3lIv5 QDR7fiX2liuT79TceSaHbBMNbbC0+mdiqLqI36tev9ej8lE3a1otAXHV8FuJNXiUmTxv+CFf/ h+RFmcKme3NBdV36rRS/CXtNKDV4LTaxRVUJDE2pWEr3QYo0W9I+n3F4JdVMwWEfMBmKFcgZh kwNVos00kuEgqWKNkXfNLXdJRuKQ/lTUfxhpFALEqYVYk= > In amdgpu_connector_add_common_modes(), the return value of drm_cvt_mode= () > is assigned to mode, which will lead to a NULL pointer dereference on > failure of drm_cvt_mode(). Add a check to avoid npd. Can a wording approach (like the following) be a better change description= ? A null pointer is stored in the local variable =E2=80=9Cmode=E2=80=9D a= fter a call of the function =E2=80=9Cdrm_cvt_mode=E2=80=9D failed. This pointer was= passed to a subsequent call of the function =E2=80=9Cdrm_mode_probed_add=E2=80=9D= where an undesirable dereference will be performed then. Thus add a corresponding return value check. Would you like to add any tags (like =E2=80=9CFixes=E2=80=9D) accordingly? How do you think about to use a summary phrase like =E2=80=9CAvoid null po= inter dereference in amdgpu_connector_add_common_modes()=E2=80=9D? Regards, Markus