From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422866AbWJOIDy (ORCPT ); Sun, 15 Oct 2006 04:03:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422871AbWJOIDy (ORCPT ); Sun, 15 Oct 2006 04:03:54 -0400 Received: from mail.suse.de ([195.135.220.2]:63183 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S1422866AbWJOIDw (ORCPT ); Sun, 15 Oct 2006 04:03:52 -0400 Date: Sun, 15 Oct 2006 10:03:51 +0200 From: Nick Piggin To: Robin Holt Cc: Hugh Dickins , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: [PATCH] get_user_pages(..., write==1, ...) may return with readable pte. Message-ID: <20061015080351.GA4763@wotan.suse.de> References: <20061013203342.GA21610@lnx-holt.americas.sgi.com> <20061014045305.GA23740@wotan.suse.de> <20061014101507.GA6316@lnx-holt.americas.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061014101507.GA6316@lnx-holt.americas.sgi.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 14, 2006 at 05:15:07AM -0500, Robin Holt wrote: > > dup_mmap holds mmap_sem for write. get_user_pages caller must hold it > > for read. > > I could have sworn I checked for that and found a down_read(), but > now that I look when I have some time, it is clearly a down_write(). > Sorry for the distraction. I'm one to do the same thing, don't worry ;) > It is a user job that is passing data between hosts. The host is > under heavy memory pressure and one rank of the MPI job gets silent > data corruption. http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=016eb4a0ed06a3677d67a584da901f0e9a63c666 It could be this? inode reclaim calls invalidate_inode_pages, so this one is a memory corrupter under heavy reclaim pressure. > > Thanks and sorry for wasting your time, Not at all, my pleasure.