From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: Putting for discussion "__qdisc_run" bug - strange application-dependant error Date: Sun, 10 May 2009 09:33:30 +0200 Message-ID: <4A06834A.1040307@gmail.com> References: <657221.87331.qm@web28608.mail.ukl.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Panadero Pizza Return-path: Received: from mail-bw0-f174.google.com ([209.85.218.174]:51289 "EHLO mail-bw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751352AbZEJHeJ (ORCPT ); Sun, 10 May 2009 03:34:09 -0400 Received: by bwz22 with SMTP id 22so2074685bwz.37 for ; Sun, 10 May 2009 00:34:08 -0700 (PDT) In-Reply-To: <657221.87331.qm@web28608.mail.ukl.yahoo.com> Sender: netdev-owner@vger.kernel.org List-ID: Panadero Pizza wrote, On 05/09/2009 09:55 PM: > Hello netdev group, > > I would like to put for discussion, if a bug in the __qdsic_run function could explain the problem I have described in my post "Kernel networking problem (>=2.6.24.7)" two days ago. > > "__qdisc_run" is the last common function in the kernel traces I receive for the kernels: > > 2.6.24.7 > 2.6.27.12 > > with a multi-threaded software, using fputc, putc, puts - calls, mixed with fflush()-calls on a remote file, opened on a cifs-handle. (Errors occur extremely seldom, although the software is running for hours - day after day) > > I don't receive the error with other standard software (e.g. "dd"), writing to a file on the same cifs-handle/session and more interesting: > The error does not occur with the afore-mentioned multi-threaded program (or any other software), using a > > 2.6.16.62 > > kernel. > > I have found that from 2.6.24.x on, the __qdisc_run function has been made preemptible and this feature has been enabled for the realization of the afore-said 2.6.24.7 and 2.6.27.12 kernels. > > Though 2.6.16.62 solves my problem, I am offering participation in finding a solution for this (which should be fixed, if it is a kernel bug). > Since you're suggesting the specific patch has broken this for you, could you simply write if 2.6.24.4 (or 2.6.24.7 with "NET: Add preemption point in qdisc_run" patch reverted) also solves your problem? Btw., you've admitted the stack could be a problem; did you try to enable any kernel debugging for this? Cheers, Jarek P. PS: continuing the discussion within one thread and limiting line width would make it easier to track this report.