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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 600B0C433F5 for ; Wed, 11 May 2022 22:16:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A24FF6B0074; Wed, 11 May 2022 18:16:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9FBDE6B0075; Wed, 11 May 2022 18:16:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8EB3F8D0001; Wed, 11 May 2022 18:16:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 80B0E6B0074 for ; Wed, 11 May 2022 18:16:51 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 51E122FF8C for ; Wed, 11 May 2022 22:16:51 +0000 (UTC) X-FDA: 79454873022.10.368AAA4 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf09.hostedemail.com (Postfix) with ESMTP id ADD3214009A for ; Wed, 11 May 2022 22:16:42 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F3B2D61C19; Wed, 11 May 2022 22:16:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAD5BC34114; Wed, 11 May 2022 22:16:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652307409; bh=Ibde5NPEHI+ISPFgedToJYypsoPY3AeS1t76w6zY15I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=BCg9Cb/JqTWEFBaFeifnbSh1qLq5VOBjWYNYv/gj1oOtaFLzCU/xMtY5sWNsLtAlO 8OqLupmESdbdbC/Q5rULO9VehhCL90jcWPraHcb1J/A3U7pr3hZyDGioScABaNol+m rv1a+efCJXUZj/Eanz4+aNtF4QgZ4d+W2W/Dr87VDAqMFG1Stv3+E3F96k5EwEGL82 SdkgSfp+ret2wivonAM/Oqy32ld6Ug3dGf1sBZ/r2TtyfDpJt3R8Qj1U+innFOIowH NtdwlkmZgWFGBou4CPPChUtmSzvoAgPjwnuBBxvO6o29qS6s8cBIRySUu622psNrHr nrnO9bWL+zAXg== Date: Wed, 11 May 2022 15:16:47 -0700 From: Jakub Kicinski To: Kees Cook Cc: "Matthew Wilcox (Oracle)" , Christoph Hellwig , "David S. Miller" , Paolo Abeni , Du Cheng , Christophe JAILLET , Vlastimil Babka , William Kucharski , Arnd Bergmann , Nathan Chancellor , netdev@vger.kernel.org, linux-mm@kvack.org, linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] niu: Silence randstruct warnings Message-ID: <20220511151647.7290adbe@kernel.org> In-Reply-To: <20220510205729.3574400-1-keescook@chromium.org> References: <20220510205729.3574400-1-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: ADD3214009A Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="BCg9Cb/J"; spf=pass (imf09.hostedemail.com: domain of kuba@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=kuba@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspam-User: X-Stat-Signature: rgwuyws9kcys7zjfkdb7bmyciss9r1jo X-HE-Tag: 1652307402-228437 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: On Tue, 10 May 2022 13:57:29 -0700 Kees Cook wrote: > Clang randstruct gets upset when it sees struct addresspace (which is > randomized) being assigned to a struct page (which is not randomized): > > drivers/net/ethernet/sun/niu.c:3385:12: error: casting from randomized structure pointer type 'struct address_space *' to 'struct page *' > *link = (struct page *) page->mapping; > ^ > > It looks like niu.c is looking for an in-line place to chain its allocated > pages together and is overloading the "mapping" member, as it is unused. > This is very non-standard, and is expected to be cleaned up in the > future[1], but there is no "correct" way to handle it today. > > No meaningful machine code changes result after this change, and source > readability is improved. > > Drop the randstruct exception now that there is no "confusing" cross-type > assignment. > > [1] https://lore.kernel.org/lkml/YnqgjVoMDu5v9PNG@casper.infradead.org/ > > Cc: "Matthew Wilcox (Oracle)" > Cc: Christoph Hellwig > Cc: "David S. Miller" > Cc: Jakub Kicinski > Cc: Paolo Abeni > Cc: Du Cheng > Cc: Christophe JAILLET > Cc: Vlastimil Babka > Cc: William Kucharski > Cc: Arnd Bergmann > Cc: Nathan Chancellor > Cc: netdev@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: linux-hardening@vger.kernel.org > Signed-off-by: Kees Cook I presume you prefer to take this one via your tree too, so: Acked-by: Jakub Kicinski