From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71]) by kanga.kvack.org (Postfix) with ESMTP id 42F196B0005 for ; Mon, 11 Jun 2018 17:58:13 -0400 (EDT) Received: by mail-pl0-f71.google.com with SMTP id y7-v6so12736538plt.17 for ; Mon, 11 Jun 2018 14:58:13 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id l12-v6si23297619pfb.69.2018.06.11.14.58.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 11 Jun 2018 14:58:11 -0700 (PDT) Date: Mon, 11 Jun 2018 14:58:09 -0700 From: Andrew Morton Subject: Re: [PATCH v11 3/7] mm: fix __gup_device_huge vs unmap Message-Id: <20180611145809.c05f215b9b2e7dab9e808304@linux-foundation.org> In-Reply-To: <152669370864.34337.13815113039455146564.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152669369110.34337.14271778212195820353.stgit@dwillia2-desk3.amr.corp.intel.com> <152669370864.34337.13815113039455146564.stgit@dwillia2-desk3.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams Cc: linux-nvdimm@lists.01.org, stable@vger.kernel.org, Jan Kara , david@fromorbit.com, hch@lst.de, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org On Fri, 18 May 2018 18:35:08 -0700 Dan Williams wrote: > get_user_pages_fast() for device pages is missing the typical validation > that all page references have been taken while the mapping was valid. > Without this validation truncate operations can not reliably coordinate > against new page reference events like O_DIRECT. > > Cc: I'm not seeing anything in the changelog which justifies a -stable backport. ie: a description of the end-user-visible effects of the bug?