From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: Data corruption issue with splice() on 2.6.27.10 Date: Tue, 6 Jan 2009 19:37:05 +0100 Message-ID: <20090106183704.GC32491@kernel.dk> References: <20081224152841.GB13113@1wt.eu> <20090106183223.GA11964@ioremap.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Willy Tarreau , linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Evgeniy Polyakov Return-path: Received: from brick.kernel.dk ([93.163.65.50]:29598 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751672AbZAFSiK (ORCPT ); Tue, 6 Jan 2009 13:38:10 -0500 Content-Disposition: inline In-Reply-To: <20090106183223.GA11964@ioremap.net> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Jan 06 2009, Evgeniy Polyakov wrote: > Hi Willy. > > Unfortunately I can not work on this problem right now, but will do if > things are not resolved after Jan 11 (long vacations will be finished in > Russia and I will return to my test machines :) But right now I have > one quesstion: I read several times your mail but still can not figure > out if receiving or sending side is broken? > > I.e. can you splice from socket into the file, check the file, and then > splice to the another socket and check received data to find out which > side is broken? Or did I just missed that in the problem description? > > Thanks a lot for the test application, it will greatly help to resolve > this issue. I'll give this a spin tomorrow as well. A hunch tells me that this is likely a page reuse issue, that splice is getting the reference to the buffer dropped before the data has really been transmitted. IOW, the page is likely fine reaching the ->sendpage() bit, but will be reused before the data has actually been transmitted. So once you get that far, other random data from that page is going out. Just a guess, I'll try and reproduce this tomorrow! -- Jens Axboe