From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53262 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752997AbdLGMEy (ORCPT ); Thu, 7 Dec 2017 07:04:54 -0500 Date: Thu, 7 Dec 2017 13:05:01 +0100 From: Greg Kroah-Hartman To: Jack Wang Cc: "Kirill A. Shutemov" , Andrea Arcangeli , Hillf Danton , stable@vger.kernel.org, Andrew Morton , Linus Torvalds Subject: Re: [PATCH 1/3] thp: reduce indentation level in change_huge_pmd() Message-ID: <20171207120501.GA6159@kroah.com> References: <1512642172-7981-1-git-send-email-jinpu.wangl@profitbricks.com> <1512642172-7981-2-git-send-email-jinpu.wangl@profitbricks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1512642172-7981-2-git-send-email-jinpu.wangl@profitbricks.com> Sender: stable-owner@vger.kernel.org List-ID: On Thu, Dec 07, 2017 at 11:22:50AM +0100, Jack Wang wrote: > From: "Kirill A. Shutemov" > > commit 0a85e51d37645e9ce57e5e1a30859e07810ed07c upstream. > > Patch series "thp: fix few MADV_DONTNEED races" > > For MADV_DONTNEED to work properly with huge pages, it's critical to not > clear pmd intermittently unless you hold down_write(mmap_sem). > > Otherwise MADV_DONTNEED can miss the THP which can lead to userspace > breakage. > > See example of such race in commit message of patch 2/4. > > All these races are found by code inspection. I haven't seen them > triggered. I don't think it's worth to apply them to stable@. > > This patch (of 4): What about all 4 of these? And should this also go into 4.9? I don't want to include fixes into 4.4-stable without them also being in 4.9-stable, as that would be a regression for people upgrading. thanks, greg k-h