From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 49DB81E906C; Mon, 21 Oct 2024 13:14:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729516465; cv=none; b=HgazJ/u07m5m09wmPnrV9duYqsBtCp7JXRDfGtKlBN4sMpu3mibx69Zlil1fxkSp+7+S7PzRyWG3Ogkd+V6PyRbBuqSL0s6pvJhbjwqkHfAzISSmaK6TvwQfHu1GXVOWgGPy4fvtwUezvsjk4fQI57r1Apw7osg++dXanrfdGAs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729516465; c=relaxed/simple; bh=OPT5AbxfJYRmwQf7O59ti/U6BN1gWoe3PBxjcsD4Oy8=; h=From:To:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=YX+qF1u9jGoOo7XR8yGiaM9Kq3g6u452q5H2fe3LbKkBdGOrDbcTRR5gAzJe6wbydM2TJhrgANlk18BEwR4NtbNGnA4OEV4OwZP3vPqo4t58mZG9zYiv1XKQz4OFubKws8b/WPDSLcfllviI0CZVs29fjYczs8usc9INJSC+C5s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mF5QUNjW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mF5QUNjW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79886C4CEC3; Mon, 21 Oct 2024 13:14:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729516464; bh=OPT5AbxfJYRmwQf7O59ti/U6BN1gWoe3PBxjcsD4Oy8=; h=From:To:Subject:In-Reply-To:References:Date:From; b=mF5QUNjWAyemP13yIZEigUjZDcIaiI5NUuT9BJZruFdXivO7jvXVXWO7agFbF6RFJ rQQK7CtjCfUwj38GJUU+V900DEyszmzR1UgexjDtiaEOKWjTi2U2BjkBSd8PQ6mB23 wrQzlhhV4c6+VcF2JDS0nrAEN6ZuLcHwTE3lKJRof57QqDUK4Z7AVvPfeTsNQBP723 ZDFTSeF0uPpwYy1rU4HGJUkV8pimDA2THaRbHtKLZTEo9bNiv+7NM14s+gKA6o/vdQ p0qGd2jAO4y6Hbs7ST9aewCMth3kCSXlnH9ZDEsmcLFBh31VadoyqtvFdgI8XRRxLa 0CZfZfoHFY5lQ== From: Puranjay Mohan To: Helge Deller , 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 Subject: Re: [PATCH bpf-next 3/5] selftests/bpf: don't mask result of bpf_csum_diff() in test_verifier In-Reply-To: <31b8ea3b-f765-43c0-9cee-49bc13064f04@gmx.de> References: <20241021122112.101513-1-puranjay@kernel.org> <20241021122112.101513-4-puranjay@kernel.org> <31b8ea3b-f765-43c0-9cee-49bc13064f04@gmx.de> Date: Mon, 21 Oct 2024 13:14:04 +0000 Message-ID: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" --=-=-= Content-Type: text/plain 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 = 0; \ >> r5 = 0; \ >> call %[bpf_csum_diff]; \ >> -l0_%=: r0 &= 0xffff; \ >> - exit; \ >> +l0_%=: exit; \ > > Instead of dropping the masking, would it make sense to > check here if (r0 >> 16) == 0 ? We define the expected value in R0 to be 65507(0xffe3) in the line at the top: __success __retval(65507) So, we should just not do anything to R0 and it should contain this value after returning from bpf_csum_diff() This masking hack was added in: 6185266c5a853 ("selftests/bpf: Mask bpf_csum_diff() return value to 16 bits 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 Thanks, Puranjay --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iIoEARYKADIWIQQ3wHGvVs/5bdl78BKwwPkjG3B2nQUCZxZTnRQccHVyYW5qYXlA a2VybmVsLm9yZwAKCRCwwPkjG3B2ndk3AP0XXZde0lRtwFVwJrCkF/VkxqH1qoIW YzgfJHIpSZzNAAEA0eN6ggg1/3zV3pUq6bqFbBaa+ah8TtqqUbVVefg8aAI= =vDn9 -----END PGP SIGNATURE----- --=-=-=--