From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.gmx.net (mout.gmx.net [212.227.15.19]) (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 AC5A01DF754; Mon, 21 Oct 2024 14:05:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.227.15.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729519505; cv=none; b=AHm20M+KxJ0088z/syDipwtANSs8tbX5zAUdVERMrWoO5u1SPyysZmmAc/X4CwZfd7gxhJsJNOrJ2QGxCy9SrTuhw6mOf9DpcO8sk1IVrOVSFfTyZH+uxScy+K/Z63jedzBBPoFYm91icdz0YDbQXlweD+3PgfVof9VfcdZNMDs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729519505; c=relaxed/simple; bh=C05g4q8NdYBCSJK1fcpzMahjm+yq9IbNNxfA3gK1GdI=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=KcTGt9fNj06MLwiq9yG+GPoSY5LruHJfNIhmE2s6V37QNJAZ3b+TpVLwK5AjqjXE4LtXkmy9spXiq3WVB90rsxJvfHJbk7ALxMmtWJGjABw001aUruWn8Y9aSvUUAHYpBEoLJtLTbt3lKbFT79L9p9+XihtcVBGB+lPKzjXkukg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gmx.de; spf=pass smtp.mailfrom=gmx.de; dkim=pass (2048-bit key) header.d=gmx.de header.i=deller@gmx.de header.b=pdGRBy7X; arc=none smtp.client-ip=212.227.15.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gmx.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmx.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmx.de header.i=deller@gmx.de header.b="pdGRBy7X" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmx.de; s=s31663417; t=1729519466; x=1730124266; i=deller@gmx.de; bh=KHEHhgl3vT2qa4XlTJ64Ck+WkTzRu0oSpPZLUl326jE=; h=X-UI-Sender-Class:Message-ID:Date:MIME-Version:Subject:To: References: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=pdGRBy7XwsouqsLdYc7G5M1qa5UoGswFupmj2UQAxuH9EXyJcv/gkpHgXthvvrv+ 2LelATXe8AQUx9w0qtwANm35+1wxOmLjclJ1RMhK/W4gI212eXYDYUgZWKwwG93wT mLjaXJi3US4JsYwffySS/FrgSaE/X3uOmk9x7oi43dZlrIFmiDHA4xnjLK3mxwheC uFSlCNvvtBsR9f30IuTsA3uzlZZC22aE27oK009fe5gd8Pz88UGH5nJOaKis+x0Xv 8Zz+dCpt31rR0fjgY6g0KRjXUgRWlkpLETnHg22ocjdHlIYtMQsEUTF1Bq9cZOMDK dOix/CnkEr+jJ7tfQA== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from [10.8.0.6] ([78.94.87.245]) by mail.gmx.net (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1M3lY1-1t2blp04OZ-004rkb; Mon, 21 Oct 2024 16:04:26 +0200 Message-ID: Date: Mon, 21 Oct 2024 16:04:22 +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 Subject: Re: [PATCH bpf-next 3/5] selftests/bpf: don't mask result of bpf_csum_diff() in test_verifier To: Puranjay Mohan , Albert Ou , Alexei Starovoitov , Andrew Morton , Andrii Nakryiko , bpf@vger.kernel.org, Daniel Borkmann , "David S. Miller" , Eduard Zingerman , Eric Dumazet , Hao Luo , Jakub Kicinski , "James E.J. Bottomley" , Jiri Olsa , John Fastabend , KP Singh , linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, Martin KaFai Lau , Mykola Lysenko , netdev@vger.kernel.org, Palmer Dabbelt , Paolo Abeni , Paul Walmsley , Shuah Khan , Song Liu , Stanislav Fomichev , Yonghong Song References: <20241021122112.101513-1-puranjay@kernel.org> <20241021122112.101513-4-puranjay@kernel.org> <31b8ea3b-f765-43c0-9cee-49bc13064f04@gmx.de> Content-Language: en-US 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: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:uk4z+Tqi+SiUY+nEn2TK7BhJ0ZpV9jMDshA/W528bXZKEkkNaZ4 JMf6Xd5p8sIfmm0L7rAKVRwVSVhtl7pa5iVTSrBl3GnC87Ntt6iq3mm6dfEIr2y6Xg4P88K xYEWaOPOOk1C9ckmm7/bKS/YRRCfbB7+0zs6RN229wxmZ0PoCLh+Dzn0kKkHvhMIxWtIDzY K5e9rOgqkCvYC5qThd6Tg== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:wcd4v2NSwZw=;UtD5g5TLmzKEUxPdvj7ZFt7oKDD IGWXP+UcG1t6DSUGhW3EVgEYfaojtGkv77LssLRlsRuRBYPP4wlLq+Pd2ZLo/vy9h5pTkl8Ff Ivp3PnHsJJ/h/PqNWEWvAHToWOYeIqh0F5TWBNooPK4O8nOOweiMTrqubXfZ0Xl+eW0vwnXVN sBXsPUgiZ8ffSTTjek3vXQ1Yx7AaEDbZcqdXwzCbSaij4cB08EXsxC3SZhC94Kv6kFtr9pfif Fwy1oCgwuv6ptvD6ypc4tD1BduiXSWNXf0lyTZUyjn+bw3IQXLoambBXhbgjFGrSY5B1uvL+p 0QTPfShfMrb42BBn6gk5hM/XyNUSD4klSYpa6sp7xRVQJ1l4ho3741Mpcl39CWVQn/zHDu6nx MWxcNZXlXaWloQY9qcnLatEC0lEeisq60RGZyJEpteN4TlmFktfyfER6EuHQZiXFFYuugHEOz JfLNDi15xWmN+qHfVmiXipV95hCY8xikSvJzDRny8enhOG5drVDhBsmzqK936we2kPp5IH7E4 o4BQ9rkE4V+XK8ODIfrROaPDSbk078vFAIrTx0I8WbbzwOI2v+HRqujta3MJu5dLQjj4MC3MW 18w7i/hhYtHXkp7LZxVj/a/eXLmPfAu7GouPWMLcQJ9//4MLRT9aAzhDiGB0yT43OVVJyqLhl AAdb872De7AD0mXWCaiFykeZeRRorT0AP65KRwECzAlOfuCKDJk5v+tVjZVIoFTZEUW0xpgZ/ t25VbUyIr22rln/DPHMrfXuhNbK6sMY14p9sPS0Oze0w1w2+SZeUYGl+8s6AzrTws1d82uxP3 CR+UQIiXd0roAPrshDWivJbg== On 10/21/24 15:14, Puranjay Mohan wrote: > Helge Deller writes: > >> On 10/21/24 14:21, Puranjay Mohan wrote: >>> The bpf_csum_diff() helper has been fixed to return a 16-bit value for >>> all archs, so now we don't need to mask the result. >>> >>> ... >>> --- a/tools/testing/selftests/bpf/progs/verifier_array_access.c >>> +++ b/tools/testing/selftests/bpf/progs/verifier_array_access.c >>> @@ -368,8 +368,7 @@ __naked void a_read_only_array_2_1(void) >>> r4 =3D 0; \ >>> r5 =3D 0; \ >>> call %[bpf_csum_diff]; \ >>> -l0_%=3D: r0 &=3D 0xffff; \ >>> - exit; \ >>> +l0_%=3D: exit; \ >> >> Instead of dropping the masking, would it make sense to >> check here if (r0 >> 16) =3D=3D 0 ? > > We define the expected value in R0 to be 65507(0xffe3) in the line at th= e top: > __success __retval(65507) > > So, we should just not do anything to R0 and it should contain this valu= e > after returning from bpf_csum_diff() > > This masking hack was added in: > > 6185266c5a853 ("selftests/bpf: Mask bpf_csum_diff() return value to 16 b= its in test_verifier") > > because without the fix in patch 2 bpf_csum_diff() would return the > following for this test: > > x86 : -29 : 0xffffffe3 > generic (arm64, riscv) : 65507 : 0x0000ffe3 You're right. Thanks for explaining. Helge