From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2ED2DC4361B for ; Thu, 17 Dec 2020 17:44:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2C14235DD for ; Thu, 17 Dec 2020 17:44:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729330AbgLQRoV (ORCPT ); Thu, 17 Dec 2020 12:44:21 -0500 Received: from mout.gmx.net ([212.227.15.19]:52633 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727388AbgLQRoU (ORCPT ); Thu, 17 Dec 2020 12:44:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1608226965; bh=UkUU0la/6Jv7MXQfdCTccvvTqgYQDgGpJ6ZlfjZav90=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=fgNr88QbhYjpSHWs1SECbu8WoCwineyXNBU5FoTm85MzGsNCa1HCMVixCPE6trCbz Nvytz2N194PoPMyB2Ou8hI3AoaZhxFXO1jp48FveSiC3fcRNREUGFho3wmH2chEf4m 97K9h2MuncRLrSZVn4JdfD5eYEloc5LzR9WOTQ/4= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [192.168.20.60] ([92.116.140.151]) by mail.gmx.com (mrgmx004 [212.227.17.190]) with ESMTPSA (Nemesis) id 1N0oFz-1jvVFw2Iq5-00wmWM; Thu, 17 Dec 2020 18:42:45 +0100 Subject: Re: [PATCH] checkpatch: add new warning when lookup_symbol_name() is used To: Joe Perches , Andy Whitcroft , linux-kernel@vger.kernel.org References: <20201217171111.GA8295@ls3530.fritz.box> <816c1571b4132f991089b40a759cf68afcf4af43.camel@perches.com> From: Helge Deller Autocrypt: addr=deller@gmx.de; keydata= mQINBF3Ia3MBEAD3nmWzMgQByYAWnb9cNqspnkb2GLVKzhoH2QD4eRpyDLA/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/qmRFnKVQARAQABtBxIZWxnZSBEZWxs ZXIgPGRlbGxlckBnbXguZGU+iQJRBBMBCAA7AhsDBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheA FiEERUSCKCzZENvvPSX4Pl89BKeiRgMFAl3J1zsCGQEACgkQPl89BKeiRgNK7xAAg6kJTPje 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9C8Gwtq7d4eUql8Nd3dAk767avoQiwZeTgoLVb1suBSEtkT65KcCZLkaKjl8lK+wEuTv8jXkC hKa0lztAiYbI3BGlX6OyNcCMGuBBixU0YMkCL7Lzl3j0q3zBPfRIbbY9+lwaBWkyCMBFfNxNP zwxYn87Wt4svOKNGUDq0uU9ize51fc02N+bb/bX00HZPlw7X0BYPJB7ftS5ItTbeMXMC2iFzo dpzXCjvESoLRywnPIKVFPSga8AUWnR7GmTnvbwv4LAsYUugn2anygnp/ynV/eLqlt2q83vCiY uDtXv4SvYbt2hUS6YtKokKVF7DXbNYSzMu6ADkSX5QLjAMJDZrfc/9Kq24eqK8sEDk0txJBmc 0nn1t1HjMMee5yRGNagDmsH7NM+TWxT9dVkD+BHQhQrrQwRwf2DmqPqpJU5HK4bUXjTnq65QU AOapQZjgX/k+uR44cjMSvzaV1W6Myw6PTuUvJCvCfZxd2/17mYaeB/p+jwg0/mhU5+ZVbcAg/ j2CMwMyu8eFNZ/+xzV6soadsQb7C1Bwi6oeE3Zr/4sEYu0Xrpd/jb5TSIUutqEuP+2+OGNlpn tTkoXfk69wbXzUyQMaP9c5+pVOXFHSUdKWE8PY4WXFD5f6xTBbnY1lpyE7l5YmCbmPTlv1deV xgVeeb4ld/kqwnuDNJysjjy+IE+Ne6UJO5CefrAdQSIRQmmp8rd9psbfIcXoXtp8kQ2j6G7tQ 7AJ2SsS5nQORQbiRVVXN7AAKu47k6tdfDRsSuOtqYTGgm0w94Q7mX7aFBOMtNi21tatHkarIr MK/vxqx8PwfrPXNSX6nrAbi1v4Abuh9q8Kz5ACocURVzNfVS/CatqlCy1ui0W8PHyVSHf0OFu r5yvVJDsvd+Z00gxz/YQ== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/17/20 6:27 PM, Joe Perches wrote: > On Thu, 2020-12-17 at 18:11 +0100, Helge Deller wrote: >> In most cases people use lookup_symbol_name() to resolve a kernel symbo= l >> and then print it via printk(). >> >> In such cases using the %ps, %pS, %pSR or %pB printk formats are easier >> to use and thus should be preferred. > [] >> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl > [] >> @@ -4317,6 +4317,12 @@ sub process { >> =C2=A0 "LINUX_VERSION_CODE should be avoided, code should be for= the version to which it is merged\n" . $herecurr); >> =C2=A0 } >> >> +# avoid lookup_symbol_name() >> + if ($line =3D~ /\blookup_symbol_name\b/) { >> + WARN("PREFER_PRINTK_FORMAT", >> + "If possible prefer %ps or %pS printk format string to print s= ymbol name instead of using lookup_symbol_name()\n" . $herecurr); >> + } >> + >> =C2=A0# check for uses of printk_ratelimit >> =C2=A0 if ($line =3D~ /\bprintk_ratelimit\s*\(/) { >> =C2=A0 WARN("PRINTK_RATELIMITED", > > Huh? nak. > > lookup_symbol_name is used in the kernel a grand total of 3 times. Yes, there were much more in the past which got fixed by patches I submitt= ed. > 2 uses are kprobe, the other is fs/proc Right. For fs/proc see: https://lore.kernel.org/lkml/20201217165413.GA1959@ls3530.fritz.box/ > None of the existing uses is equivalent to %ps Yes, those are the remaining legimate users. > Why should this be applied? ... to prevent people to add new code with possibly unjustified use? Helge