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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 EE513C282DE for ; Wed, 5 Jun 2019 09:10:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE42020866 for ; Wed, 5 Jun 2019 09:10:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qsKJodQe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726958AbfFEJKn (ORCPT ); Wed, 5 Jun 2019 05:10:43 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:39511 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726502AbfFEJKn (ORCPT ); Wed, 5 Jun 2019 05:10:43 -0400 Received: by mail-pl1-f196.google.com with SMTP id g9so9461056plm.6 for ; Wed, 05 Jun 2019 02:10:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=A0F5TwKY/VCSLcp+XKNpiRnciFopNfIc4l3QtF9bGnE=; b=qsKJodQeWHQrpBSUsCV/81Z7vFl9IiPrLe7Wx+TTMYwOb8vRhY7qMbyumwt8N6nzUp huDpz/WgJhGZQJNcubX5sDMOT5m/6LbguxcPIte89UJaj/B9lKADRPVtqIepVB+oX5sd hnXgkLK8L2MAW5lPvWDC99pJ4HSaC8QE332V5c6l5n9kmFfM5U7iJgD+3HoP8nJY6/oe T2TGY4+lUrdaa/iyrZ9+h1U0EN1aUJNorBJTwurwt7/FrvQoDKhFU75jWXstBB47BFp4 vZG8Ouj9I7fWnXUOm8nkebeHXwU6K1NcK2iJ+B0SMP3aK6IXE+yb2bmKcQto4teTeueg RHKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=A0F5TwKY/VCSLcp+XKNpiRnciFopNfIc4l3QtF9bGnE=; b=fA5br/hzAN9IYWMvPcnXrm2Tas4QHys4d7+yV6XU77qXOYq9OEB+EJDOTuylcnJtlk QYNWb8YjbaYSFOFYjBS+LKjMhvbqOP1aOck3yjANWACjl/faMvUnVSKqoeDeavwKgMeo fj2oeYr2gK5xEdcU70JVxm5TxsL4i1A/Js61HBi+aOTHv5BCJAyz8YhYPl5up1MsWRyf RMk1lcd3c62hJ904nZJ0RmlIuy1fzoyGQM1F3jwvxiW5S6xQpfeTMxTZN/7G4QSMLpVu lpZbpQ3PQrwr1pqfjWCO41CmGozKsbRoS1hwEQsaH3ra5AFbUm6wHUd1SS+DZAdIl+wh jtlw== X-Gm-Message-State: APjAAAVWf0EVia7eHPvj5i2XYA3a/+zuAd7BNpAQBhUeYaCS8Tt2J+a3 9iHZ0mJdcxX6WRKYgm7gUA== X-Google-Smtp-Source: APXvYqwPrprfYIFcfp2U4RhBi6aA36+dRA/hHPLVJndUrShnel3Up//HynanoblmvqR0aoxy92SoVg== X-Received: by 2002:a17:902:624:: with SMTP id 33mr42733906plg.325.1559725842640; Wed, 05 Jun 2019 02:10:42 -0700 (PDT) Received: from mylaptop.nay.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id w36sm11844525pgl.62.2019.06.05.02.10.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Jun 2019 02:10:39 -0700 (PDT) From: Pingfan Liu To: linux-mm@kvack.org Cc: Pingfan Liu , Ira Weiny , Andrew Morton , Mike Rapoport , Dan Williams , Matthew Wilcox , John Hubbard , "Aneesh Kumar K.V" , Keith Busch , Christoph Hellwig , linux-kernel@vger.kernel.org Subject: [PATCHv3 1/2] mm/gup: fix omission of check on FOLL_LONGTERM in get_user_pages_fast() Date: Wed, 5 Jun 2019 17:10:19 +0800 Message-Id: <1559725820-26138-1-git-send-email-kernelfans@gmail.com> X-Mailer: git-send-email 2.7.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As for FOLL_LONGTERM, it is checked in the slow path __gup_longterm_unlocked(). But it is not checked in the fast path, which means a possible leak of CMA page to longterm pinned requirement through this crack. Place a check in the fast path. Signed-off-by: Pingfan Liu Cc: Ira Weiny Cc: Andrew Morton Cc: Mike Rapoport Cc: Dan Williams Cc: Matthew Wilcox Cc: John Hubbard Cc: "Aneesh Kumar K.V" Cc: Keith Busch Cc: Christoph Hellwig Cc: linux-kernel@vger.kernel.org --- mm/gup.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index f173fcb..0e59af9 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2196,6 +2196,26 @@ static int __gup_longterm_unlocked(unsigned long start, int nr_pages, return ret; } +#ifdef CONFIG_CMA +static inline int reject_cma_pages(int nr_pinned, struct page **pages) +{ + int i; + + for (i = 0; i < nr_pinned; i++) + if (is_migrate_cma_page(pages[i])) { + put_user_pages(pages + i, nr_pinned - i); + return i; + } + + return nr_pinned; +} +#else +static inline int reject_cma_pages(int nr_pinned, struct page **pages) +{ + return nr_pinned; +} +#endif + /** * get_user_pages_fast() - pin user pages in memory * @start: starting user address @@ -2236,6 +2256,9 @@ int get_user_pages_fast(unsigned long start, int nr_pages, ret = nr; } + if (unlikely(gup_flags & FOLL_LONGTERM) && nr) + nr = reject_cma_pages(nr, pages); + if (nr < nr_pages) { /* Try to get the remaining pages with get_user_pages */ start += nr << PAGE_SHIFT; -- 2.7.5