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 0BBBAC433EF for ; Fri, 7 Jan 2022 23:44:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 410276B0072; Fri, 7 Jan 2022 18:44:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3BF076B0073; Fri, 7 Jan 2022 18:44:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 286A86B0074; Fri, 7 Jan 2022 18:44:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0114.hostedemail.com [216.40.44.114]) by kanga.kvack.org (Postfix) with ESMTP id 1A1A66B0072 for ; Fri, 7 Jan 2022 18:44:35 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id C385F824C43C for ; Fri, 7 Jan 2022 23:44:34 +0000 (UTC) X-FDA: 79005122868.29.8350E0F Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf16.hostedemail.com (Postfix) with ESMTP id 5C3CA180007 for ; Fri, 7 Jan 2022 23:44:34 +0000 (UTC) Received: from mail.kernel.org (unknown [198.145.29.99]) (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 5F4AF61E56; Fri, 7 Jan 2022 23:44:33 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 954D760F02; Fri, 7 Jan 2022 23:44:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1641599072; bh=mFW9jLRAhoR62vEi6kr1oh7XBJ3e/Fq1hbvzXDZvlLQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nHw662ABuBwKSE/w8YwQ4aHlfxmBHcel3EpKDjR0hDdcq8ZqESZci3HUpXqpdr7hP AlXKItDDJNzQA1oPGh75YW61s5Y8ufJm8KOy0HSQoTZCfIFI8DbAtItb+vJOsmRjYg OxYhSiOPyTSjxBATYpqwU35R1vB6KcccIGRxiubo= Date: Fri, 7 Jan 2022 15:44:30 -0800 From: Andrew Morton To: Helge Deller Cc: Linux Kernel , linux-mm@kvack.org, linux-parisc@vger.kernel.org Subject: Re: [PATCH] usercopy: Do not fail on memory from former init sections Message-Id: <20220107154430.1bd6252e66baada7d84bdd6c@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 5C3CA180007 X-Stat-Signature: jmsteah63i56m5hsg5t1frzy1n6j87cf Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=nHw662AB; dmarc=none; spf=pass (imf16.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam02 X-HE-Tag: 1641599074-474127 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000018, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 7 Jan 2022 01:19:24 +0100 Helge Deller wrote: > On some platforms the memory area between the _stext and the _etext > symbols includes the init sections (parisc and csky). If the init > sections are freed after bootup, the kernel may reuse this memory. > > In one test the usercopy checks if the given address is inside the .text > section (from _stext to _etext), and it wrongly fails on the mentioned > platforms if the memory is from the former init section. > > Fix this failure by first checking against the init sections before > checking against the _stext/_etext section. This sounds like it might have very serious runtime effects? Please always fully describe a bug's runtime effects when fixing that bug. > Fixes: 98400ad75e95 ("parisc: Fix backtrace to always include init funtion names") So is this a must-have for 5.16?