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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 480A9CFD356 for ; Mon, 24 Nov 2025 21:43:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5BDF16B0029; Mon, 24 Nov 2025 16:43:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 547216B002A; Mon, 24 Nov 2025 16:43:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 435BF6B002B; Mon, 24 Nov 2025 16:43:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 2AE336B0029 for ; Mon, 24 Nov 2025 16:43:02 -0500 (EST) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id B7B4789B98 for ; Mon, 24 Nov 2025 21:42:56 +0000 (UTC) X-FDA: 84146825952.02.60B7B18 Received: from mail-ej1-f46.google.com (mail-ej1-f46.google.com [209.85.218.46]) by imf28.hostedemail.com (Postfix) with ESMTP id 88933C0015 for ; Mon, 24 Nov 2025 21:42:54 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=g5r19vNc; spf=pass (imf28.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.218.46 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1764020574; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NoAYUzaUy2oENd7JkoqDPVCvDLLlV10MU8wdc2FsfGw=; b=I4pt6o/XShYSstYGPeW8uiQxDkV1w0msXXOC1D8LzqU+wqCv/BNUq/wc6wk5fiV18O6U8z dJShVJ4hWkewMzxVqTCezTzpK93sLVN5tsnNP2vgaMhLcCbzknIQkAgpZgpOluXz4zBFsl 5PDiIYndFI1orhkYiIHlH4Woxy6dSLI= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=g5r19vNc; spf=pass (imf28.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.218.46 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1764020574; a=rsa-sha256; cv=none; b=6aeo/rGF5Gw1nzm4IAUsT+vwZaBZzGxkSfKbecNPRzcBIBQZm1AvHf+4xj8vfYinhMp/DB d9XSEpi8jQnUrg0g+uGUfiMvBcWcvq/Cswz0R//rhTw6PznR+HuvrCPWu3eWzc8fQy9pQA AUlNwLH1GfNKVX8m46BVQF0kncFGIhE= Received: by mail-ej1-f46.google.com with SMTP id a640c23a62f3a-b7355f6ef12so1013353066b.3 for ; Mon, 24 Nov 2025 13:42:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; t=1764020573; x=1764625373; darn=kvack.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=NoAYUzaUy2oENd7JkoqDPVCvDLLlV10MU8wdc2FsfGw=; b=g5r19vNc6RYRpiub6A8vOzLrEUUb8e+8QS1RswKviijfmSzoQafiVaD3SnQjQWj8Ry cZxDEEi8n0c0texcRPP0J5sHAW9LnTLkYm1T4PT99h/3c14SWr3SARU+OfdXbCpqPAf6 xbztM/j3WwcJu8f7kjTvv6z5uKT5RXVflqTQ0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764020573; x=1764625373; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=NoAYUzaUy2oENd7JkoqDPVCvDLLlV10MU8wdc2FsfGw=; b=hLu8goOk46aP3hT7DD6csQ5MqAhdXV/Nnw9TaM9mfLqMFlzpYNRVr4qM8M68xssDYO G6W4yXoTObDZLTSU/GkBztt2NIvWyn/dPAyYahk7Dw93B6CHpOfKAUOJIbab7qSjh83N mDe/QNbdu1waerfDNQyg8Ahj5vFl/H7dZFOTahvJC7oDV20dljEzmQdr8O7Qgw+EyLZJ aEpZzFr5RK0O/t1Zix+JgbRnO/RYCR5n1q+dODHSxsvI1MeJ9qFqFwOx3SN4SFJXbnt9 a6bhEp/NCiUcjDFjGWZwZXEHA5weDuP5RVC5OEO9VWz6m9Se9/vb4w6GA74l2eqf1Lga TgYQ== X-Forwarded-Encrypted: i=1; AJvYcCU/Ir32uQOz05BCbm4zpbOv1W43lNlYN2c9QncFcBYDClRuxPReP23krO0VhcGMDkyjTJYKCdueqg==@kvack.org X-Gm-Message-State: AOJu0YyX8Y8dLXRBDDzRzYjKIPjYt/whW2Dj15wXTai4EkJdIfOVo9Ow 1xLcOiALbLCYWwh4EI8aSkYqEcQ7owXPMXIP5BtBGm/k5KFDM9U0MO1WrM0LarZTHN6XwjN/Ll5 v3dXxQys= X-Gm-Gg: ASbGncsyszem59Mc43PW/GbYKNw8nLF3tiAG8H2Ka1KF4Nhx6fc8nZ0YUsSlMbIY/Gb MOwk+/tSp0STYhTDXnqly7t3oWufHGt7zv4tFn2lg2E3gtdyGPABLY0wrYJiPyU8y/mX5Pihif8 73gmK/UV26lI6vn6rfYeOB58S/5O7BqGGbZvql6y311DLMOGAvvVRjLJOvURWnVPWCaTIyhueg1 3m1DOWMlyAzHHew89T2YaUa6hQpV2nBwsEQIKdtmB8L025XmNgt9BKBou9ijjmf7Jc/ZzvXMKWO 4mc9t+QLo8ytXSEQG8giDz3NJp45dGLJqDP64H5SLeNlheONSKp5ceYVBrrSbGkOd56HC8X3cdt 2oaSsUQtCpWywrJN0uqpoRkWp0OldZrWw+EahSxVzHjUOkEAdHW8jBqsGfV+7USud/s2UEOU802 f4M4pfjyKegxQfa+S76tN93hDgWajwQZFv8vvunmVdboSZBt1rKGp1W84GgIjM X-Google-Smtp-Source: AGHT+IHF4rWrw6vh8iGlo67n5wF5pw/sIhtqsseTUA9P1k7+hrJkPQ8T43WR9w5mMYC76i73UfL8fg== X-Received: by 2002:a17:907:7286:b0:b3d:73e1:d809 with SMTP id a640c23a62f3a-b767173270emr1761093566b.48.1764020572485; Mon, 24 Nov 2025 13:42:52 -0800 (PST) Received: from mail-ej1-f53.google.com (mail-ej1-f53.google.com. [209.85.218.53]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b765504828esm1389665066b.64.2025.11.24.13.42.52 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 24 Nov 2025 13:42:52 -0800 (PST) Received: by mail-ej1-f53.google.com with SMTP id a640c23a62f3a-b7355f6ef12so1013348466b.3 for ; Mon, 24 Nov 2025 13:42:52 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCULZBfidnjcC7lYWL+EDT8M3wNskrRueDJVcj1SVL+SCkHVKad6m2aaf6ZdnEGPKW0DHaDQHn+KqQ==@kvack.org X-Received: by 2002:a17:907:dab:b0:b73:4fbb:37a2 with SMTP id a640c23a62f3a-b7671514106mr1495344566b.5.1764020128744; Mon, 24 Nov 2025 13:35:28 -0800 (PST) MIME-Version: 1.0 References: <20251122014258.do.018-kees@kernel.org> <20251122014304.3417954-2-kees@kernel.org> <202511241119.C547DEF80@keescook> In-Reply-To: <202511241119.C547DEF80@keescook> From: Linus Torvalds Date: Mon, 24 Nov 2025 13:35:12 -0800 X-Gmail-Original-Message-ID: X-Gm-Features: AWmQ_blKFpIgLGtxfT-s5R89X15xCb9TiduKsCJf35qbsynIOkmHF3dcQigtmSE Message-ID: Subject: Re: [PATCH v5 2/4] slab: Introduce kmalloc_obj() and family To: Kees Cook Cc: Vlastimil Babka , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, "Gustavo A . R . Silva" , Bill Wendling , Justin Stitt , Jann Horn , Przemek Kitszel , Marco Elver , Greg Kroah-Hartman , Sasha Levin , linux-mm@kvack.org, Randy Dunlap , Miguel Ojeda , Matthew Wilcox , Vegard Nossum , Harry Yoo , Nathan Chancellor , Peter Zijlstra , Nick Desaulniers , Jonathan Corbet , Jakub Kicinski , Yafang Shao , Tony Ambardar , Alexander Lobakin , Jan Hendrik Farr , Alexander Potapenko , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, linux-doc@vger.kernel.org, llvm@lists.linux.dev Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 88933C0015 X-Stat-Signature: hdmmjg15i7567fwfncqobfninmhjjois X-Rspamd-Server: rspam02 X-Rspam-User: X-HE-Tag: 1764020574-785249 X-HE-Meta: U2FsdGVkX1/Y7OvhQ6iGk57WAW/tNkHq5I+ond3GlS5oNG4wbcBxyHdHs+GtQaIGuEp5lMKyE3o+oinJTv5mIaEx9O5Irb4ql+BAxnDhtD4odOIltN+OQWPBcnHGcYu7bKwY+99TEOKmd02iXJnVr9uO5KDWslFQcf+Q4fWUjnIJEMWydKQoCdEhRVbbvmaLHSQUvYxMsnB7vl7FQZPCNfxCfZlbppd7NAz1TroPv57NQEUfPa7qGed3It3E2YqGvyjpv09e5vLPt6BnYSQ9fGI5uX7hhQt5J9v2apv+FlJhGUWV8QSHE87ocdusyusgd6PHaX787XS9cxtcFaCTSna8SdhLEi22630//l6UNTM8D/hTJ1msysHoQCQKmQK+d58bzy9fHvDw+WEHzd8kkmyK9sFt6R5OONho1ewpYubSnR47qLMqbui5fhoMiXatkFYqBMOFB3I5jxpMvW1ah6RuiZuoLBpw3oe6GUZwwDtGg+GU5Eqfszak98cAuXlZKdanFK8/7nN9uujXc1FYNBC8wINQ3dZ6FmX6PLEYZGmHg8AxSj32wOeg1JfEAV1M4J99KBk+saZqSSIDLLfeSORgj2sLOgJD4Mim1xaQZTfwvMAFWsxDWY2JoMBPQvHK1RQVKvKRHqzygT3Dkh2uyk0Xwg59XuiyEDANptFuSUHbCKjE4LwTp6LYkWyVV/GgE5ofXDguc2mWdUUDBKcbjb9Bzc9PJho8Lxt8evG+nwRj6QDNBv9mFNc5vY4Z01Wak56l9n8lsdj1CDFt2kd2zMrRslC2zulvcQgct2FEwXdAI8K9zSG3Cezhp/0JnKlfyCMIn8eHOSjuqc9DZPrE8WF4IyqGb+jYCzgDwBRjgXyfOusREcqY8lbGM60V6jP9slTTRqq42yhrhoiXTpLQy4otTCZGR4ZniEqEjRT/qRkh/BkAHlO8zo398CsOq9lDSynnDnQs8dBrnD6p2JT z1ITN8Xp 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 24 Nov 2025 at 12:39, Kees Cook wrote: > > I'm not sure what you mean by "limit to pre-defined size". There's no > such design in those helpers, except from the perspective of "detect > and refuse to truncate overflows into too-small storage". Is that what > you meant? I meant that odd combination of checking both for minimal size and then assigning to it, but upon re-reading it, I realize that the "check for minimal size" was actually checking the size of the result variable. Those macros are illegible. And 99% of all users DO NOT WANT ANY OF THAT COMPLEXITY. Yes, the wrapper macros then pass in NULL, which then - using yet more complexity - turns into a dummy thing. Basically, if *I* find those macros unreadable - and I'm actually fairly good at parsing those things - then they are way too complicated. And they aren't even complicated for a good reason. My alternate ones did *more*, and did it with less code and less confusion. And you added the complication to make the users less legible. So no. We're not doing *any* of that. You make it simple and targeted to the *common* case, of you don't do this at all. Because that over-designed mess that actually turned some users *less* readable, but one line shorter, was bad. Linus