From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.web.de (mout.web.de [212.227.15.4]) (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 8CC9613D89B; Wed, 26 Jun 2024 12:18:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.227.15.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719404320; cv=none; b=EeD+1/MDkdImTTA4D0AdDNBQwy/zSzlDEAWL9NneXX/kRHHII1klQxzr5Xu+JCRzlW6H/8DAEyjqJqRy78awGWBwAreeW8Ki+knZOmdH1LdXknRZMkq3b7hBcEJE9nbo9zPzBOwkhMzyMNJu56fhZUr3+z/kfI9F/JAQSUJxXfY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719404320; c=relaxed/simple; bh=2x37NzR/2lEZeNq0vRkCFXPL3a+/btL9FCqu5MrlKVg=; h=Message-ID:Date:MIME-Version:To:Cc:References:Subject:From: In-Reply-To:Content-Type; b=ub9bN7jjxJ7bVRoGsVfjaGxhsJ4NYHC6gVbXHthTs1FQSfhs0/dEOxiDAkWF4Bu9ewrAO9AS594ZR/faym4+6KWThcThq4Yx1SJomydg/PJl0Z46K1FdiD74MStT8JbZXHjVmatPH70czFr7J8xyVtEivSF2aPjwluVlE5ieMbU= 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=OrNn3f1X; arc=none smtp.client-ip=212.227.15.4 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="OrNn3f1X" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=web.de; s=s29768273; t=1719404288; x=1720009088; i=markus.elfring@web.de; bh=yUPAIAof3AkzY+BmPwggZrxS5owZtdhbXK8kkUOSg5c=; 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=OrNn3f1X2IUD5M4sIr9wqstdaJaB72n7F4OiQN/C4hhyFZd/tw7A0+GNPYfGQNtq k8O8NLzl8Xdqtvq/09CWapuEueBn8eQSTCoYftkMbwTerLYwQJg+yKutf66C0zLaM FB4pN9iBH0PSn5BIgZclTJxldgH4GcPK+LWGkUeA/ios8DseolRFH0jZbIFDNO+uG 6jVjb3M8fm7HgucbaEaGev2Z0vazbQ6s+5Y/QjG9vqFjg7xLFfJSxf/NizWb74q19 XbOfIOcCD6czEahZilGZfnPCrbcVsD7c/shJFP0wLwIhd+p5nEfp3Jt+Yn9j+P0tm XFTZLD7DGXSYBdgKQA== X-UI-Sender-Class: 814a7b36-bfc1-4dae-8640-3722d8ec6cd6 Received: from [192.168.178.21] ([94.31.91.95]) by smtp.web.de (mrweb006 [213.165.67.108]) with ESMTPSA (Nemesis) id 1N30ZN-1sSSoc3rPZ-00sdVt; Wed, 26 Jun 2024 14:18:07 +0200 Message-ID: <7efdcd35-7511-491a-a0b2-c500ebb2256d@web.de> Date: Wed, 26 Jun 2024 14:18:06 +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 , dri-devel@lists.freedesktop.org, spice-devel@lists.freedesktop.org, virtualization@lists.linux.dev, Daniel Vetter , Dave Airlie , Gerd Hoffmann , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann Cc: LKML , David Airlie References: <20240626064024.2811255-1-make24@iscas.ac.cn> Subject: Re: [PATCH] drm/qxl: fix null pointer dereference in qxl_add_mode Content-Language: en-GB From: Markus Elfring In-Reply-To: <20240626064024.2811255-1-make24@iscas.ac.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:C60OHFSjUuj7c1Ny1z+3dfhRyGU9CgYduGDl5Y0uOjNWFaNRIBg pZn9Q1V4E276IQizd99IZn+VBG3/z4MThrqGn+8Zf43SzQz9WiXCEuvVJq53xuWJGmsubrO A+k/2CYu4mODi/iGDVY6OwkP55j6PQzl9r/vRNqwosZBvTUXyQcRdzvzfXq0RKHg/Y6SccJ tIoZ/gnAkHy1336uFBbig== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:8l6RBOATA38=;k3Ef5uHGkoup54xiTgrtslyJhyB 8qsV6Y68qgY1O30UVdyYKXiZJiWeypvHKHgXUYOTEpgUR1F6dstjJ1FWWM1SFR+3YC+BJIEUB Uy86NirTHEraqqqf5DVheVAnFIPyCogdGluIZknBWrx09x2M3V+ganzKkjy885E6F2E23h1vc Hma/UYfAs3KN6AfrAZhU8wRyfi3Nh0z2zXv2OYj/mDRndnB7SGBq6ZBy7yZSzWL/6lpB/lpiV N32AqwSRwVx2k/o55YSMxDCyJzkYSaSbdRNy/uO40QWLE69mLKc6Ir7eLBGNYUXn9jzvmMLap ODT37KSAGcydgciEDT4y3M2UJ8W+XS/GVLaKNAcjGiIarKUU4medUIn2Fc4rNa7WGjEqZ302H a4g04HAn8U95oYPkX6M0+Dqsrbdb2cXvfVPrfN/FNiDsINxoClU4UcBF6FWrH3O1r+1oO5E3W qdMTQA0l0bT6o0YuHTpr8LpkxNXfmAK1WyvtaSOLE18AvxqfYvBFJi/Ae/8xGLJ0dPnMHzwHd RIiASKB6tyTkjNLqX/dQIPDwsZC7R8DQ2j0ZgPEw7HC6g8lMI8PI7J839xXk3aKXW60bo9GAB NxemrNOs+c87ww5r/EQaRinoJe9x1ZcrUlttenTgiv0MZu1ALqZdFMK+H+3aCETpOr3oQu1uY ZtyTcf1F+XYPiYAWkFtcFMXcEBWSkkjYwlj8Onl6SgMR7iLNLh1pfYSx03d1QWrisg8t22cTZ qaHfMBT3NnkZwruCDIBxKDL7yQdjpsvNUTNtTWjXOa24He+gL7cmaxfWMZsyb4NOBGGtaHQO/ i32qOJYTULauwOM+r/guAnVvsBUiYHFmOHcisD9uF8y78= > In qxl_add_mode(), the return value of drm_cvt_mode() is assigned to mod= e, > which will lead to a possible NULL pointer dereference on failure of > drm_cvt_mode(). Add a check to avoid npd. 1. Can a wording approach (like the following) be a better change descript= ion? 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= used in subsequent statements where an undesirable dereference will be performed then. Thus add a corresponding return value check. 2. Would you like to add any tags (like =E2=80=9CFixes=E2=80=9D and =E2=80= =9CCc=E2=80=9D) accordingly? 3. How do you think about to append parentheses to the function name in the summary phrase? Regards, Markus