Received: by 10.213.65.68 with SMTP id h4csp2646033imn;
        Mon, 9 Apr 2018 06:55:57 -0700 (PDT)
X-Google-Smtp-Source: AIpwx4+zCco9YhzD8XnyX5qz1F6DskImvijV151AzJ4vHXrU94wqXC6j9N5ptrogNB/NcORuHFO3
X-Received: by 10.98.17.210 with SMTP id 79mr29408174pfr.65.1523282157261;
        Mon, 09 Apr 2018 06:55:57 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; t=1523282157; cv=none;
        d=google.com; s=arc-20160816;
        b=L7tdbgQ+S650Q863rCuJiTxXgUsjMJ1XFqKrvA624aOYitTBK/FbjfrF0q+e0hqtSQ
         pTl3/OWkqu89o1bH59fWjR2kUYENvg655fjLku+5nr7EBH12OiSHQWtxEGhR98EYVy4h
         VnzzdayslDWql2OZZuygqTno+27KHbRhmvH2V87SEM4rV7R0f9BJ7CgLAEtd1FQDn/ns
         Hqe+jMclJ3sC7rJg6vQI3cfVW+1WX//M295gsQcbbvzn0ehppFvhyuUCvq6rsl+MKATr
         b6fYvyb+jutpPbNVJbYpeBQZanqP4qy3NV/JU/IDNqkOuCrixmn+zakvZBhTAr6DjJR2
         2M0w==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
        h=list-id:precedence:sender:user-agent:in-reply-to
         :content-disposition:mime-version:references:message-id:subject:cc
         :to:from:date:dkim-signature:arc-authentication-results;
        bh=2tpg/FdoGNprNw4DBIdBumzygJkllJsDoSiwGDqVgs0=;
        b=RdBx+FXaXVYiiBJvQ0krQRfiLuXGJb+5PLP/93bsSdOv2ZKjbxIVVg1Hier0dq8e4+
         sNPye4JXeME8ubNpuayTjcbwjXxx8CqgYybzk4ZKnb+tJPJBZEl3jbqpwiKZsZpWLYvj
         YYcq1h07QQ5QhoejxJ0aLd32msq5V6XYGP7UOJ6rIqMuk61FLA3qHZ/UjDfmyawvj6zf
         Vds81N3kcAAVwK/JvXi2dT6zcG1BxYjWLZk6K4Xl+RfRYb95a2RINcuj7UFoYoZ5gfXI
         zGEFODk/KxKqNhkHT1SBYMKAi2KXQS8yjuaAqK8jcTn2gwb8CUKn/HN731gjH7uWVJPO
         N4pA==
ARC-Authentication-Results: i=1; mx.google.com;
       dkim=fail header.i=@infradead.org header.s=bombadil.20170209 header.b=oMmB1m6v;
       spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67])
        by mx.google.com with ESMTP id n8si259183pgt.480.2018.04.09.06.55.18;
        Mon, 09 Apr 2018 06:55:57 -0700 (PDT)
Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Authentication-Results: mx.google.com;
       dkim=fail header.i=@infradead.org header.s=bombadil.20170209 header.b=oMmB1m6v;
       spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751991AbeDINvM (ORCPT <rfc822;gklkml16@gmail.com> + 99 others);
        Mon, 9 Apr 2018 09:51:12 -0400
Received: from bombadil.infradead.org ([198.137.202.133]:35006 "EHLO
        bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751539AbeDINvK (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 9 Apr 2018 09:51:10 -0400
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
        d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version
        :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:
        Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date:
        Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:
        List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive;
         bh=2tpg/FdoGNprNw4DBIdBumzygJkllJsDoSiwGDqVgs0=; b=oMmB1m6vbhUK8uKVpeOfHlEEk
        OxuheCIlasTY00QHLnpwfp+LPNnjTwa8d2qVS0MOq7yuaFsOInf8rKbspBt09zozzJ1XeQGd0J7FE
        B4JckwwXqj15ERFx8gE62HtsImAfCB+SqUMhoiivWpFYKw0tQbRtpu6zrdwFzPTClr1LX7krmITOc
        l9Zuk5zmzJZON9f5olrO85Zvu6wx2z231ujaRzK6dAd0E7B/Vd2EHoC+asUE/N4XhM3OLEigvY+47
        MKExf28nXzWLejoc5PS1H61JA5DII9sAXLNyHVIfJulvKQaRgGuZ9uXDCC35Y5pgvsOUgr/XSfVPm
        kmXGLPTmw==;
Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux))
        id 1f5XCK-0000qL-Lq; Mon, 09 Apr 2018 13:51:04 +0000
Date:   Mon, 9 Apr 2018 06:51:04 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Michal Hocko <mhocko@kernel.org>, Chao Yu <yuchao0@huawei.com>,
        Minchan Kim <minchan@kernel.org>,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Christopher Lameter <cl@linux.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>, Jan Kara <jack@suse.cz>,
        Chris Fries <cfries@google.com>,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] mm: workingset: fix NULL ptr dereference
Message-ID: <20180409135104.GA23434@infradead.org>
References: <20180409015815.235943-1-minchan@kernel.org>
 <20180409024925.GA21889@bombadil.infradead.org>
 <20180409030930.GA214930@rodete-desktop-imager.corp.google.com>
 <20180409111403.GA31652@bombadil.infradead.org>
 <20180409112514.GA195937@rodete-laptop-imager.corp.google.com>
 <7706245c-2661-f28b-f7f9-8f11e1ae932b@huawei.com>
 <20180409124852.GE21835@dhcp22.suse.cz>
 <20180409134114.GA30963@bombadil.infradead.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20180409134114.GA30963@bombadil.infradead.org>
User-Agent: Mutt/1.9.2 (2017-12-15)
X-SRS-Rewrite: SMTP reverse-path rewritten from <hch@infradead.org> by bombadil.infradead.org. See http://www.infradead.org/rpr.html
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, Apr 09, 2018 at 06:41:14AM -0700, Matthew Wilcox wrote:
> It's worth noting that this is endemic in filesystems.

For the rationale in XFS take a look at commit ad22c7a043c2cc6792820e6c5da699935933e87d