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 72996ECAAD1 for ; Sat, 27 Aug 2022 03:19:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C08196B0074; Fri, 26 Aug 2022 23:19:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BB92D940007; Fri, 26 Aug 2022 23:19:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A80096B007B; Fri, 26 Aug 2022 23:19:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 986D26B0074 for ; Fri, 26 Aug 2022 23:19:44 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 72E5FC059F for ; Sat, 27 Aug 2022 03:19:44 +0000 (UTC) X-FDA: 79843917888.10.A598E2E Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf13.hostedemail.com (Postfix) with ESMTP id F2FC720022 for ; Sat, 27 Aug 2022 03:19:43 +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 4201861DB6; Sat, 27 Aug 2022 03:19:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2770CC433D6; Sat, 27 Aug 2022 03:19:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1661570382; bh=l8bh0UlqdzPrtkN84q9zam96jL20dAmmD1ZErVl3gEg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=t5iUjlv6LPyc6Md5JdsZoQqIcCardc+IfYCGnm4NiFchCaQ1EqVxwfp82AB4wXlmx w5u+ogExFpSIHDvlgSZl7OdBKoNu3yEmG60oS1BM5rJHe3l0Q2IuVz48qEftrsGdQP tiDDxgGQS55yEwaPAj9By1hGkwDL0dNyp7FSEVJ0= Date: Fri, 26 Aug 2022 20:19:41 -0700 From: Andrew Morton To: Charan Teja Kalla Cc: , , , , , , , , , , , , Subject: Re: [PATCH V5] mm: fix use-after free of page_ext after race with memory-offline Message-Id: <20220826201941.de6ed957a0d6547b2d501c19@linux-foundation.org> In-Reply-To: <1661496993-11473-1-git-send-email-quic_charante@quicinc.com> References: <1661496993-11473-1-git-send-email-quic_charante@quicinc.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661570384; a=rsa-sha256; cv=none; b=gMebwORZerY97Gdw28VEmnnS9YE2TKKG/38iOV/RSVpXzdCUrWrKNyluoy7oKGishCPW3e TdefJ8UJ21K66E5TET/RKUzHSwSi9tVsaxJnaQ0/Flr94bcuC+yGc+B0sLtkQBZMQGD+iL xr/wTAtPALBL0FmxIGgdCYh3vLzkKNI= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=t5iUjlv6; spf=pass (imf13.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661570384; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=uJHXlGi+sh4a9lad8ng9l4zsuc2VvGOePiVmd6apspw=; b=GtWr7EGj1hLFOtXpOKzSwchvynAAV/h+ZgUAQKVWZWuDWJ9kpORZuvWB5KG9MMiXiYa3rp jW4ETneSL3h/6njHuc61ui8ZtK92mHTVfcWFmfKvYWnsRnCWNe5OBH3xGkS6OpjFQmSYUf Vm67akG+gSwqvX+6TDC0qiSq6DZh0Uw= X-Rspam-User: Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=t5iUjlv6; spf=pass (imf13.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspamd-Server: rspam10 X-Stat-Signature: aoy1nzned6ojzpzsxjaqdwjjoin9mfpj X-Rspamd-Queue-Id: F2FC720022 X-HE-Tag: 1661570383-895853 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 Fri, 26 Aug 2022 12:26:33 +0530 Charan Teja Kalla wrote: > The below is one path where race between page_ext and offline of the > respective memory blocks will cause use-after-free on the access of > page_ext structure. What are people's thoughts on a -stable backport? It looks like the bug has been there for years and the means of hitting it are obscure and the patch isn't minor, so I'm thinking no?