From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265082AbUEYTxe (ORCPT ); Tue, 25 May 2004 15:53:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265087AbUEYTvE (ORCPT ); Tue, 25 May 2004 15:51:04 -0400 Received: from fw.osdl.org ([65.172.181.6]:47258 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S265082AbUEYTrx (ORCPT ); Tue, 25 May 2004 15:47:53 -0400 Date: Tue, 25 May 2004 12:47:15 -0700 From: Andrew Morton To: joe.korty@ccur.com Cc: markh@compro.net, linux-kernel@vger.kernel.org Subject: Re: mlockall and mmap of IO devices don't mix Message-Id: <20040525124715.5f7e61b6.akpm@osdl.org> In-Reply-To: <20040525142728.GA10738@tsunami.ccur.com> References: <20031003214411.GA25802@rudolph.ccur.com> <40ADE959.822F1C23@compro.net> <20040521191326.58100086.akpm@osdl.org> <20040525142728.GA10738@tsunami.ccur.com> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Joe Korty wrote: > > On Fri, May 21, 2004 at 07:13:26PM -0700, Andrew Morton wrote: > > Mark Hounschell wrote: > > > > > > Joe Korty wrote: > > > > > > > > 2.6.0-test6: the use of mlockall(2) in a process that has mmap(2)ed > > > > the registers of an IO device will hang that process uninterruptibly. > > > > The task runs in an infinite loop in get_user_pages(), invoking > > > > follow_page() forever. > > > > > > > > Using binary search I discovered that the problem was introduced > > > > in 2.5.14, specifically in ChangeSetKey > > > > > > > > zippel@linux-m68k.org|ChangeSet|20020503210330|37095 > > > > > > > > > > I know this is an old thread but can anyone tell me if this problem is > > > resolved in the current 2.6.6 kernel? > > > > > > > There's an utterly ancient patch in -mm which might fix this. > > > > http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.6/2.6.6-mm4/broken-out/get_user_pages-handle-VM_IO.patch > > [ 2nd send -- corporate email system in the throes of being scrambled / updated ] > > Andrew, > I have been using this patch for ages. Any chance of it being forwared to > the official tree? That patch had its first birthday last week. I wrote it in response to some long-forgotten problem, failed to changelog it at the time then forgot why I wrote it. I kept it in the hope that I'd remember why I wrote it. I subsequently wrote a best-effort changelog but am unconvinced by it. Ho hum. Let me genuflect a bit. I guess we can be reasonably confident it won't break anything.