From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 7F9A230347 for ; Wed, 8 Nov 2023 15:39:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmx.de header.i=deller@gmx.de header.b="MVoryq9a" Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B8D6138; Wed, 8 Nov 2023 07:39:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.de; s=s31663417; t=1699457920; x=1700062720; i=deller@gmx.de; bh=RQou+busEXK1el5zagRtSD2v4f/DHN4LUnOWxuImoNc=; h=X-UI-Sender-Class:Date:Subject:To:Cc:References:From: In-Reply-To; b=MVoryq9aaD0lgknM+UykwFhr5H8QWMEsO8Ivs+H0RX38+Yoq2lpvcwUXRqsP4ssp 9MyqRQGuza8yUUkXHpWXCtYrXg22Hu15Qq9iWRXemfFi4zVLnC+KBn7ZMtNBXXR5l x9pf8UpCCfscsNVfFfa3z69nbq2HrtBg/cjPdZBWEFY0LdPAOxv+rrj8b4cveEjqI 6rGj0uUD3ALOkGv5F9goOa9RP4CyGYtqom0+nUnSHconA2EYThZYAXWBvh4vRX1te agHhUOmuhj+02AoOOFDTeJ6z4j8hBt18x/ShQ7AOeIg7JFS5y0kHd9hQN/T4+r5jR RWQ+QOf51XI4dy7DtA== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from [192.168.20.60] ([94.134.158.7]) by mail.gmx.net (mrgmx104 [212.227.17.168]) with ESMTPSA (Nemesis) id 1M59C8-1r1r6K0dUa-0017cZ; Wed, 08 Nov 2023 16:38:40 +0100 Message-ID: Date: Wed, 8 Nov 2023 16:38:34 +0100 Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] fbdev: hyperv_fb: fix uninitialized local variable use Content-Language: en-US To: Arnd Bergmann , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Greg Kroah-Hartman , Javier Martinez Canillas , Arnd Bergmann Cc: kernel test robot , Dan Carpenter , Thomas Zimmermann , Michael Kelley , "Guilherme G. Piccoli" , "Kirill A. Shutemov" , Dawei Li , linux-hyperv@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20231108145822.3955219-1-arnd@kernel.org> From: Helge Deller Autocrypt: addr=deller@gmx.de; keydata= xsFNBF3Ia3MBEAD3nmWzMgQByYAWnb9cNqspnkb2GLVKzhoH2QD4eRpyDLA/3smlClbeKkWT HLnjgkbPFDmcmCz5V0Wv1mKYRClAHPCIBIJgyICqqUZo2qGmKstUx3pFAiztlXBANpRECgwJ r+8w6mkccOM9GhoPU0vMaD/UVJcJQzvrxVHO8EHS36aUkjKd6cOpdVbCt3qx8cEhCmaFEO6u CL+k5AZQoABbFQEBocZE1/lSYzaHkcHrjn4cQjc3CffXnUVYwlo8EYOtAHgMDC39s9a7S90L 69l6G73lYBD/Br5lnDPlG6dKfGFZZpQ1h8/x+Qz366Ojfq9MuuRJg7ZQpe6foiOtqwKym/zV dVvSdOOc5sHSpfwu5+BVAAyBd6hw4NddlAQUjHSRs3zJ9OfrEx2d3mIfXZ7+pMhZ7qX0Axlq Lq+B5cfLpzkPAgKn11tfXFxP+hcPHIts0bnDz4EEp+HraW+oRCH2m57Y9zhcJTOJaLw4YpTY GRUlF076vZ2Hz/xMEvIJddRGId7UXZgH9a32NDf+BUjWEZvFt1wFSW1r7zb7oGCwZMy2LI/G aHQv/N0NeFMd28z+deyxd0k1CGefHJuJcOJDVtcE1rGQ43aDhWSpXvXKDj42vFD2We6uIo9D 1VNre2+uAxFzqqf026H6cH8hin9Vnx7p3uq3Dka/Y/qmRFnKVQARAQABzRxIZWxnZSBEZWxs ZXIgPGRlbGxlckBnbXguZGU+wsGRBBMBCAA7AhsDBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheA FiEERUSCKCzZENvvPSX4Pl89BKeiRgMFAl3J1zsCGQEACgkQPl89BKeiRgNK7xAAg6kJTPje uBm9PJTUxXaoaLJFXbYdSPfXhqX/BI9Xi2VzhwC2nSmizdFbeobQBTtRIz5LPhjk95t11q0s uP5htzNISPpwxiYZGKrNnXfcPlziI2bUtlz4ke34cLK6MIl1kbS0/kJBxhiXyvyTWk2JmkMi REjR84lCMAoJd1OM9XGFOg94BT5aLlEKFcld9qj7B4UFpma8RbRUpUWdo0omAEgrnhaKJwV8 qt0ULaF/kyP5qbI8iA2PAvIjq73dA4LNKdMFPG7Rw8yITQ1Vi0DlDgDT2RLvKxEQC0o3C6O4 iQq7qamsThLK0JSDRdLDnq6Phv+Yahd7sDMYuk3gIdoyczRkXzncWAYq7XTWl7nZYBVXG1D8 gkdclsnHzEKpTQIzn/rGyZshsjL4pxVUIpw/vdfx8oNRLKj7iduf11g2kFP71e9v2PP94ik3 Xi9oszP+fP770J0B8QM8w745BrcQm41SsILjArK+5mMHrYhM4ZFN7aipK3UXDNs3vjN+t0zi qErzlrxXtsX4J6nqjs/mF9frVkpv7OTAzj7pjFHv0Bu8pRm4AyW6Y5/H6jOup6nkJdP/AFDu 5ImdlA0jhr3iLk9s9WnjBUHyMYu+HD7qR3yhX6uWxg2oB2FWVMRLXbPEt2hRGq09rVQS7DBy dbZgPwou7pD8MTfQhGmDJFKm2jvOwU0EXchrcwEQAOsDQjdtPeaRt8EP2pc8tG+g9eiiX9Sh rX87SLSeKF6uHpEJ3VbhafIU6A7hy7RcIJnQz0hEUdXjH774B8YD3JKnAtfAyuIU2/rOGa/v UN4BY6U6TVIOv9piVQByBthGQh4YHhePSKtPzK9Pv/6rd8H3IWnJK/dXiUDQllkedrENXrZp eLUjhyp94ooo9XqRl44YqlsrSUh+BzW7wqwfmu26UjmAzIZYVCPCq5IjD96QrhLf6naY6En3 ++tqCAWPkqKvWfRdXPOz4GK08uhcBp3jZHTVkcbo5qahVpv8Y8mzOvSIAxnIjb+cklVxjyY9 dVlrhfKiK5L+zA2fWUreVBqLs1SjfHm5OGuQ2qqzVcMYJGH/uisJn22VXB1c48yYyGv2HUN5 lC1JHQUV9734I5cczA2Gfo27nTHy3zANj4hy+s/q1adzvn7hMokU7OehwKrNXafFfwWVK3OG 1dSjWtgIv5KJi1XZk5TV6JlPZSqj4D8pUwIx3KSp0cD7xTEZATRfc47Yc+cyKcXG034tNEAc xZNTR1kMi9njdxc1wzM9T6pspTtA0vuD3ee94Dg+nDrH1As24uwfFLguiILPzpl0kLaPYYgB wumlL2nGcB6RVRRFMiAS5uOTEk+sJ/tRiQwO3K8vmaECaNJRfJC7weH+jww1Dzo0f1TP6rUa fTBRABEBAAHCwXYEGAEIACAWIQRFRIIoLNkQ2+89Jfg+Xz0Ep6JGAwUCXchrcwIbDAAKCRA+ Xz0Ep6JGAxtdEAC54NQMBwjUNqBNCMsh6WrwQwbg9tkJw718QHPw43gKFSxFIYzdBzD/YMPH l+2fFiefvmI4uNDjlyCITGSM+T6b8cA7YAKvZhzJyJSS7pRzsIKGjhk7zADL1+PJei9p9idy RbmFKo0dAL+ac0t/EZULHGPuIiavWLgwYLVoUEBwz86ZtEtVmDmEsj8ryWw75ZIarNDhV74s BdM2ffUJk3+vWe25BPcJiaZkTuFt+xt2CdbvpZv3IPrEkp9GAKof2hHdFCRKMtgxBo8Kao6p Ws/Vv68FusAi94ySuZT3fp1xGWWf5+1jX4ylC//w0Rj85QihTpA2MylORUNFvH0MRJx4mlFk XN6G+5jIIJhG46LUucQ28+VyEDNcGL3tarnkw8ngEhAbnvMJ2RTx8vGh7PssKaGzAUmNNZiG MB4mPKqvDZ02j1wp7vthQcOEg08z1+XHXb8ZZKST7yTVa5P89JymGE8CBGdQaAXnqYK3/yWf FwRDcGV6nxanxZGKEkSHHOm8jHwvQWvPP73pvuPBEPtKGLzbgd7OOcGZWtq2hNC6cRtsRdDx 4TAGMCz4j238m+2mdbdhRh3iBnWT5yPFfnv/2IjFAk+sdix1Mrr+LIDF++kiekeq0yUpDdc4 ExBy2xf6dd+tuFFBp3/VDN4U0UfG4QJ2fg19zE5Z8dS4jGIbLg== In-Reply-To: <20231108145822.3955219-1-arnd@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:FZdTMf13wFxPAhxWZWg2c1R3JIZiLXzi/PpA4Y686kMa4OeoiGp x6GgrfU4s0EUvilEfSxrx4rA7HQ8K2+0QusK1x0dx3F+fm3PUWMiVRNNlX/ynD4svy7cwYb yftFBOfAyxH9/5V5gJ/2mULmAaO/J57ltXHmoB8AmvWOAWu8n1wfw2Q+AZlu9JTvcP8LY8T 262qXyYAdhsFVuANvXxsg== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:hE/kDwUmU60=;TSD0lDDHyPmTJmerdbCVP0c9oNq 6s+JIPQ12n+ya4EhCeunURrxv4I63E656WsUxI7rfjk8ARQp+yhm94wvcOT/p6PFqqMkU0PM0 DgmboqYbkD80qovpuVrg90hNBK3T+AzRPw1A9HS/x2NhyA4y75Rfk+hIqU1OFw9cA5AqsZ+H1 lCuN34bxMFVpj+PAaGFHPBgQPlbXM5SpLmPiu/5nrjIBKSnpZBsEecNKqdaC/jd7ONzLOcLoP yXE6EoMq7KnnRDrEhUrg+dRXwDbb372t+SdhCbi2n//gMs6+DzPdj7YfCfd0phTO15EJoweiZ BlBgnLNrV/gpSP+tyxqpFrDdAVan1v1g4P5sRHWmEgkVyLPouz2nAArjZqPffs1l081/34TGq aQUR0GU7HYzHxzM+GblqI55RlGlyd72a/+wBzy7MGocW2Lv23Z8PSRmsLACncV7UymPiyCpXk hYM1oTJkcO9sk4u9Z4zdmBEdB7ULZ4pWYW2SfocwqV1gKgX9DnJBt53G3jXSzEFVMYPnEYcTa W0Tr2ur5C1OYdA8izMCxUWCKevB9xJ8MXerz0FwQHIU+lJUL1zuOCmJs+rpjFj0/0S/n/UtbF qN3xctWBFI0U7atNq8XaW3owvweBiHje3LLudMg9dDNaAYxM8of+SJSihRyEVhB3w55B61m3i mas4m21VMuowLihJnaraz0lJZvh+A8fdEi/z9z7xNbd9iI2QuJObRoJPouhZkqp6iEOBfP4zC LJwHwAGXX9pfMUSHew9WF5zRx5Pl1SQlXvTduA0Uf3VuDqXjmPQpXLvR65PJaD2xdbqn1fI/S jrJfhqiptQoW3I1aMmOjiqdBDZvHGLdOfj/hxKD+OmD9zHYJuiQ7NXax2t2niWLdEXl2hT7vf tmWfTARiAuxGpyZ4RsCI/InRvA+vQBHAFTyjdk2gPj1/JOXSCn5Ss7EMpB71+Qv9lZZUpTaj6 tM8Ia6NUFaedoGUX3e4H+TJSrpI= On 11/8/23 15:58, Arnd Bergmann wrote: > From: Arnd Bergmann > > When CONFIG_SYSFB is disabled, the hyperv_fb driver can now run into > undefined behavior on a gen2 VM, as indicated by this smatch warning: > > drivers/video/fbdev/hyperv_fb.c:1077 hvfb_getmem() error: uninitialized = symbol 'base'. > drivers/video/fbdev/hyperv_fb.c:1077 hvfb_getmem() error: uninitialized = symbol 'size'. > > Since there is no way to know the actual framebuffer in this configurati= on, > just return an allocation failure here, which should avoid the build > warning and the undefined behavior. > > Reported-by: kernel test robot > Reported-by: Dan Carpenter > Closes: https://lore.kernel.org/r/202311070802.YCpvehaz-lkp@intel.com/ > Fixes: a07b50d80ab6 ("hyperv: avoid dependency on screen_info") > Signed-off-by: Arnd Bergmann applied. Thanks! Helge > --- > drivers/video/fbdev/hyperv_fb.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyper= v_fb.c > index bf59daf862fc..a80939fe2ee6 100644 > --- a/drivers/video/fbdev/hyperv_fb.c > +++ b/drivers/video/fbdev/hyperv_fb.c > @@ -1013,6 +1013,8 @@ static int hvfb_getmem(struct hv_device *hdev, str= uct fb_info *info) > } else if (IS_ENABLED(CONFIG_SYSFB)) { > base =3D screen_info.lfb_base; > size =3D screen_info.lfb_size; > + } else { > + goto err1; > } > > /*