From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753170Ab3KSREa (ORCPT ); Tue, 19 Nov 2013 12:04:30 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:36825 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751607Ab3KSRE1 (ORCPT ); Tue, 19 Nov 2013 12:04:27 -0500 Date: Tue, 19 Nov 2013 17:04:16 +0000 From: Al Viro To: James Custer Cc: linux-mm@kvack.org, Rik van Riel , Mel Gorman , "Kirill A. Shutemov" , Jiang Liu , Michel Lespinasse , Hugh Dickins , Oleg Nesterov , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Reimplement old functionality of vm_munmap to vm_munmap_mm Message-ID: <20131119170416.GD10323@ZenIV.linux.org.uk> References: <1384878592-194909-1-git-send-email-jcuster@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1384878592-194909-1-git-send-email-jcuster@sgi.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 19, 2013 at 10:29:52AM -0600, James Custer wrote: > Commit bfce281c287a427d0841fadf5d59242757b4e620 killed the mm parameter to > vm_munmap. Although the mm parameter was not used in any in-tree kernel > modules, it is used by some out-of-tree modules. > > We create a new function vm_munmap_mm that has the same functionality as > vm_munmap, whereas vm_munmap uses current->mm, vm_munmap_mm takes the mm as > a paramter. > > Since this is a newly exported symbol it is marked EXPORT_SYMBOL_GPL. Which modules and what are they doing with it? More to the point, what prevents races with e.g. dumping core? And that's not an idle question - for example, fs/aio.c used to contain very unpleasant races of that kind exactly because it was playing games with modifying ->mm other than current->mm. In other words, NAK.