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 CA265C00140 for ; Wed, 3 Aug 2022 00:46:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 436A38E0002; Tue, 2 Aug 2022 20:46:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3E6AD8E0001; Tue, 2 Aug 2022 20:46:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2ADEB8E0002; Tue, 2 Aug 2022 20:46:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 189728E0001 for ; Tue, 2 Aug 2022 20:46:43 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id CD967140AD1 for ; Wed, 3 Aug 2022 00:46:42 +0000 (UTC) X-FDA: 79756441044.01.411A204 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf19.hostedemail.com (Postfix) with ESMTP id 6347E1A001A for ; Wed, 3 Aug 2022 00:46:41 +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 ams.source.kernel.org (Postfix) with ESMTPS id 0155AB82012; Wed, 3 Aug 2022 00:46:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68AD1C433C1; Wed, 3 Aug 2022 00:46:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1659487598; bh=IYPfZV8Mr5MahS8LdQC+lkEFagmnqzDuiBAPlmClaKo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=SPb3Z3sfcbdOAZbQhAKbGIlSRYS1+7dZ5/2YF2m8v5qtQNT089kYHC9huOuSN/tCK iM59/Nm+lZoWC15GA2Vuz771vuIwJBFssBhAzLTafBBeFaA7+4xvIpE8KCjXN0uKbK 09J2oXDiukZQIfc6LzzeIpiKPLPxLQtZyHkyhgFw= Date: Tue, 2 Aug 2022 17:46:37 -0700 From: Andrew Morton To: "Matthew Wilcox (Oracle)" Cc: Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] shmem: Update folio if shmem_replace_page() updates the page Message-Id: <20220802174637.3bd3478d137b52ef3b67c3b3@linux-foundation.org> In-Reply-To: <20220730042518.1264767-1-willy@infradead.org> References: <20220730042518.1264767-1-willy@infradead.org> 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-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659487601; 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=BTcW5U0V4mcJn/jnIDQSfJm/0ZX0rXcaRsGo50SH0DI=; b=U5nDtB8zZXKR+sy+pJMLDdMsVWj4MwvYXnjWZHhUvfOAVisiLN+r8EI8eCU8htDVkLpwT2 cvBg7wUOFPTMHBdLhSU+tstdwUAL2OEx+4y8gfM8ygTZTMtuMPQ8OlGOF1MzNWyfHKOYCj aIUbUYIAkcnvyGCB/rM0g9zAPOHWe2Q= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=SPb3Z3sf; spf=pass (imf19.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659487601; a=rsa-sha256; cv=none; b=kEqfIvAribI26cArIHVe3S5fONMKqlZaLlfVW+/8eTbpsFiVA6+v60z7FZRcSnH3BZKQtk 4ufUDNIrnlyS8Y3SEnTBwCmO1YvW6S8gf1xrhHZ7w1VpgC6wQm3XWh9dwiXgv1ZglLBula QJV4blFBPgo1fU+OgIjDmsjJ/Piy5AM= X-Rspam-User: X-Stat-Signature: 89nn9yzbm3zadpf55mx7hdhsjme7bb7r X-Rspamd-Queue-Id: 6347E1A001A Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=SPb3Z3sf; spf=pass (imf19.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspamd-Server: rspam08 X-HE-Tag: 1659487601-354697 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 Sat, 30 Jul 2022 05:25:18 +0100 "Matthew Wilcox (Oracle)" wrote: > If we allocate a new page, we need to make sure that our folio matches > that new page. This will be solved by changing shmem_replace_page() > to shmem_replace_folio(), but this is the minimal fix. > > ... > > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1771,6 +1771,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, > > if (shmem_should_replace_folio(folio, gfp)) { > error = shmem_replace_page(&page, gfp, info, index); > + folio = page_folio(page); > if (error) > goto failed; > } What are the user-visible runtime effects of the bug? Should we backport this into 5.19.X?