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 7EA4EC00140 for ; Tue, 9 Aug 2022 00:14:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9A6076B0071; Mon, 8 Aug 2022 20:14:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 92F448E0002; Mon, 8 Aug 2022 20:14:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7CFF18E0001; Mon, 8 Aug 2022 20:14:55 -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 662DC6B0071 for ; Mon, 8 Aug 2022 20:14:55 -0400 (EDT) Received: from smtpin31.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 3D27E1C6288 for ; Tue, 9 Aug 2022 00:14:55 +0000 (UTC) X-FDA: 79778133750.31.4BDAFA2 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf16.hostedemail.com (Postfix) with ESMTP id CCD1018001A for ; Tue, 9 Aug 2022 00:14:54 +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 EEA6761113; Tue, 9 Aug 2022 00:14:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BB9AC433C1; Tue, 9 Aug 2022 00:14:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1660004093; bh=s9p6n77wda0CikqJB7ybhXozw+JkQMq2Pby2cddT+uw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=B5JH0OqRDDRpkCD8xpBt/M1yyosH8jx8oAfeBOhuZrxbtP1Qf+qGQQXIDF7UvuBkd TAbwA1M621+alqShaa2kZ/WYzNdQ/iIwHPmomhM2X1bIh4E0u1YBC2wmeBKs9/1PkL s5s3m6++ktPT7RFR6KskMWssDCf8sGfVwPNnEdzs= Date: Mon, 8 Aug 2022 17:14:52 -0700 From: Andrew Morton To: Maurizio Lombardi Cc: alexander.duyck@gmail.com, kuba@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, chen45464546@163.com Subject: Re: [PATCH V3] mm: prevent page_frag_alloc() from corrupting the memory Message-Id: <20220808171452.d870753e1494b92ba2142116@linux-foundation.org> In-Reply-To: <20220715125013.247085-1-mlombard@redhat.com> References: <20220715125013.247085-1-mlombard@redhat.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=1660004094; a=rsa-sha256; cv=none; b=fKxXKLy25j/db5EYuFz4XgHo5SiHKgwPFvu3RUn6pzvd2ny8TUNb/CzgiFamop8BA9muwn 9hWQYo7hcXIY8ogsdCFgPZXTxKy/TBftet+c3XbA1ND8izVNHYjjc2lfrxKgKZMp+i4Pcq u63rh2H+IUR1txBSYYHIuv+w8vb/p9Q= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=B5JH0OqR; 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; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660004094; 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=rA3RnJotnB5RgE87/eV0/S8tWytmdX1+DrSj+NTX/7A=; b=Q+tBcfATi5EtA4J3E9Iej/zY/J5slp61EhfKUVM8yK8iFEXiHJyjWDP4bFUqc9HJ6FnVk5 ClGE2HfAgvaECyP5tgXQBIFSdCDlNKi3e/gUbaUkC+OojhUfhIZVLbxoIqHIJDmbZPUD0t na2aYKkHCUuJfij6PBIEhlQRmL1P4lA= X-Rspamd-Server: rspam06 X-Rspam-User: X-Stat-Signature: p7qarf7bikir1s44zjetku3qtmnom8mu X-Rspamd-Queue-Id: CCD1018001A Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=B5JH0OqR; 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; dmarc=none X-HE-Tag: 1660004094-400633 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, 15 Jul 2022 14:50:13 +0200 Maurizio Lombardi wrote: > A number of drivers call page_frag_alloc() with a > fragment's size > PAGE_SIZE. > In low memory conditions, __page_frag_cache_refill() may fail the order 3 > cache allocation and fall back to order 0; > In this case, the cache will be smaller than the fragment, causing > memory corruptions. > > Prevent this from happening by checking if the newly allocated cache > is large enough for the fragment; if not, the allocation will fail > and page_frag_alloc() will return NULL. Can we come up with a Fixes: for this? Should this fix be backported into -stable kernels?