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 42CE2CA1009 for ; Wed, 3 Sep 2025 18:48:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 77B738E0007; Wed, 3 Sep 2025 14:48:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 72C538E0001; Wed, 3 Sep 2025 14:48:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 641DF8E0007; Wed, 3 Sep 2025 14:48:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 5048E8E0001 for ; Wed, 3 Sep 2025 14:48:39 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id D6CCA13BA01 for ; Wed, 3 Sep 2025 18:48:38 +0000 (UTC) X-FDA: 83848825116.30.ECAC7EC Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf30.hostedemail.com (Postfix) with ESMTP id 2185C80003 for ; Wed, 3 Sep 2025 18:48:36 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=lqCnwi7N; spf=pass (imf30.hostedemail.com: domain of nathan@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=nathan@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1756925317; 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=w13NCpoyIz+MVs9GCJONudVeBM2fy+jIQB2hgsksJYY=; b=QSAQMdcw9ynVuS5xtNxMk6YGXQVpDwShzJdVkTNMYBxxAe5tCDYm85SFPAsKuU1R2R8z9r UjIh6d6ENxjIwif4k4o5BN1iOYOe2KHCVRhbjO7E0EcvWgRO7D9WngOCW/wZuXiH4Ut8l6 SrU/UIQYUvPCn+Fbi+vkz1nJ1mUBMlo= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=lqCnwi7N; spf=pass (imf30.hostedemail.com: domain of nathan@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=nathan@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1756925317; a=rsa-sha256; cv=none; b=4s5fxiGysXGCcepYZUrsvzaGyMFMGDKbXLrN+6IFCBxeDPC0rfFew2hDAtDQoTKaraP25s VlEpQ4fXX3WovcP8OIPXNxBTWppCusoTygCt0gS9+JZcuU9Sz4LG81d9O8fpGlMOIuBcAA w96AJ9wCUBab2JRqZLr8C+frPaWud9Y= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id AE05D43962; Wed, 3 Sep 2025 18:48:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 118F6C4CEE7; Wed, 3 Sep 2025 18:48:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756925315; bh=w13NCpoyIz+MVs9GCJONudVeBM2fy+jIQB2hgsksJYY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lqCnwi7NIvfcmC2zVu1A2TIXpIBlJ8B6qVPzD1+fLnRI1XnvcHoBnMnhtrS9nUnnm s8ZjGQX1kgjzh96HEwvBirTrnY4jeFenYLOlUW9DXVMoCs6X12BNZY1ajQZ+T2CmJd wwvvSfDHUuO7nvvCVgl6/2ZGEdEa3NzFh23qd2a3qXGAZCKAwh/M7HH//277MVFxM+ TDXQ1It6h35413b4i/qUw4ZpI7ueYCN2HM56Qykx6h53GqJKsHEs9Mhq362tvDBR/s t5iomFhAZA4TTbHqtIR4wfHcCCL39QkMXXmAcEbc0QjQM5v78Ki9ELP03VmgrSwK/u W7OdW+U1LGBdA== Date: Wed, 3 Sep 2025 11:48:31 -0700 From: Nathan Chancellor To: Marco Elver Cc: Alexander Potapenko , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-mm@kvack.org, llvm@lists.linux.dev Subject: Re: clang-22 -Walloc-size in mm/kfence/kfence_test.c in 6.6 and 6.1 Message-ID: <20250903184831.GA3004824@ax162> References: <20250903000752.GA2403288@ax162> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 2185C80003 X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: w4csh6ew8d637ddb6kin3c7dd3g9rs69 X-HE-Tag: 1756925316-186628 X-HE-Meta: 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 598v8ibS VSgAsHrdLWvMK0LwzLETTbV3X9meJlYwNnYReiCdEaF1EH9fnLYji/6IY0kL5vdARoP/XV10deITxVrMM0tzdBtKA69YwbAFsTKJqyv/sxKgyLIyFwsA9OT5uHKHg7winYLOlySRCBDR29KKnHP/ORx2FnGdLDVG0j3dzgCWA3f/KBM7q31pfWKFMb2hkOo1xRSaUpDmXYWV8vpS2BplsHztvBtJpJoDOfPIthvVerqNKcbdbG2+2KO1SaF4e+fXy/1wUZfhfCJ47st5zRDwM8f7qtw== 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 Wed, Sep 03, 2025 at 08:00:00AM +0200, Marco Elver wrote: > It should be silenced. I'm surprised that they'd e.g. warn about > malloc(0), which is well defined, and in the kernel, we also have > 0-sized kmalloc (incl krealloc) allocations being well-defined. As > long as the returned pointer isn't used, there's no UB. I guess doing > an explicit 0-sized alloc is not something anyone should do normally I > guess, so the warning ought to prevent that, but in the test case we > explicitly want that. Heh, just as I was looking at silencing this, I noticed a change to the warning yesterday that explicitly silences it for 0-sized allocations based on other feedback from the original thread, which I should have noticed. https://github.com/llvm/llvm-project/commit/5f38548c86c3e7bbfce3a739245d8f999e9946b5 So there is nothing to do here now, thanks for the input regardless! Cheers, Nathan