Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753396AbbEZNGC (ORCPT ); Tue, 26 May 2015 09:06:02 -0400 Received: from mail-pd0-f172.google.com ([209.85.192.172]:33267 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752655AbbEZNFx (ORCPT ); Tue, 26 May 2015 09:05:53 -0400 Date: Tue, 26 May 2015 19:22:39 +0900 From: Sergey Senozhatsky To: Daniel Phillips Cc: Jan Kara , David Lang , Rik van Riel , linux-fsdevel@vger.kernel.org, tux3@tux3.org, linux-kernel@vger.kernel.org, OGAWA Hirofumi Subject: Re: [FYI] tux3: Core changes Message-ID: <20150526102239.GA466@swordfish> References: <555D0FDF.3070303@phunq.net> <555D500B.4080901@phunq.net> <13c8bcdf-70e8-43d5-a05f-58ad839dbfd0@phunq.net> <5563F5C8.2040806@redhat.com> <67294911-1776-46b8-916d-0e5642a38725@phunq.net> <20150526070910.GA3307@quack.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1085 Lines: 26 On (05/26/15 01:08), Daniel Phillips wrote: > On Tuesday, May 26, 2015 12:09:10 AM PDT, Jan Kara wrote: > > E.g. video drivers (or infiniband or direct IO for that matter) which > >have buffers in user memory (may be mmapped file), grab references to pages > >and hand out PFNs of those pages to the hardware to store data in them... > >If you fork a page after the driver has handed PFNs to the hardware, you've > >just lost all the writes hardware will do. > > Hi Jan, > > The page forked because somebody wrote to it with write(2) or mmap write at > the same time as a video driver (or infiniband or direct IO) was doing io to > it. Isn't the application trying hard to lose data in that case? It would > not need page fork to lose data that way. > Hello, is it possible to page-fork-bomb the system by some 'malicious' app? -ss -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/