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 X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 092E1C432BE for ; Mon, 30 Aug 2021 07:00:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6E643603E7 for ; Mon, 30 Aug 2021 07:00:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 6E643603E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 83C726B006C; Mon, 30 Aug 2021 03:00:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7C29E8D0001; Mon, 30 Aug 2021 03:00:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 663AB6B0072; Mon, 30 Aug 2021 03:00:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0110.hostedemail.com [216.40.44.110]) by kanga.kvack.org (Postfix) with ESMTP id 521CB6B006C for ; Mon, 30 Aug 2021 03:00:57 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id F3A46230E2 for ; Mon, 30 Aug 2021 07:00:56 +0000 (UTC) X-FDA: 78530849712.02.C82F775 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf24.hostedemail.com (Postfix) with ESMTP id 4D5C3B0000B9 for ; Mon, 30 Aug 2021 07:00:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=cgLWd1/KVNrcv8npNVHorgwhcnZ+kDuKIO9zb2MH04o=; b=jHiwDU4mNuE0OYWISfL45EDcVO r/E6f5BeHn13lV+mFYXLSlao1+RoXROyyFwoDB3BLoW54hNd8Ya8+HqVgiUds88Sw0DtKZWFlN+r/ EAXwdYv9BuIwZExPARm/m/92vcYhvVTZR2jcMq6yK8riCQ60Tl7GHSOyartUDusRmYe0mmPIiPTk8 jaLeeUT6ZsdqN3b1mQYfqKQ3clN+jc5+vhcNm415E+p6ppPsCRCuj3Vsw8B4en3sdJLI/x55lEFc6 Y+JmWQ60fanVGow0u/ZVtNmv8psKg3W95LiaNjPr+i3IN37TZLRx69rQql+iNffiV/3CwfaEoYWTF rZBBuAuw==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mKbHT-00HQzd-PS; Mon, 30 Aug 2021 07:00:34 +0000 Date: Mon, 30 Aug 2021 08:00:31 +0100 From: Christoph Hellwig To: Yafang Shao Cc: akpm@linux-foundation.org, linux-mm@kvack.org, "Kirill A . Shutemov" Subject: Re: [PATCH] mm, gpu: fix error when FOLL_MLOCK an unpresent page Message-ID: References: <20210829011953.9051-1-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210829011953.9051-1-laoar.shao@gmail.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=jHiwDU4m; spf=none (imf24.hostedemail.com: domain of BATV@casper.srs.infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=BATV@casper.srs.infradead.org; dmarc=none X-Stat-Signature: jskhir3hcthcsdk8qu4zped5ho337izg X-Rspamd-Queue-Id: 4D5C3B0000B9 X-Rspamd-Server: rspam04 X-HE-Tag: 1630306855-776507 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 Sun, Aug 29, 2021 at 01:19:53AM +0000, Yafang Shao wrote: > After some analyzation, I found it was caused by a bug in GUP. > When the kernel module calls get_user_pages() with FOLL_MLOCK being set but > FOLL_POPULATE being unset, if the page of the user addr isn't present, the Which is not a valid way to call get_user_pages. What we need to do is to reject that case. No-tree user does this so that bug is what ever crap out of tree code you're using.