From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751410Ab2EZGRB (ORCPT ); Sat, 26 May 2012 02:17:01 -0400 Received: from mail-ey0-f174.google.com ([209.85.215.174]:36428 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751195Ab2EZGQ7 (ORCPT ); Sat, 26 May 2012 02:16:59 -0400 Subject: Re: exit_mmap BUG_ON in 2.6.23 (and Add qdisc __NET_XMIT_STOLEN) From: Eric Dumazet To: Sam Portolla Cc: Hugh Dickins , "kaber@trash.net" , "jarkao2@gmail.com" , "davem@davemloft.net" , "linux-kernel@vger.kernel.org" In-Reply-To: <1338010061.92361.YahooMailNeo@web121306.mail.ne1.yahoo.com> References: <1337406674.48432.YahooMailNeo@web121303.mail.ne1.yahoo.com> <1337992130.90506.YahooMailNeo@web121305.mail.ne1.yahoo.com> <1338006309.10135.15.camel@edumazet-glaptop> <1338010061.92361.YahooMailNeo@web121306.mail.ne1.yahoo.com> Content-Type: text/plain; charset="UTF-8" Date: Sat, 26 May 2012 08:16:55 +0200 Message-ID: <1338013015.10135.23.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2012-05-25 at 22:27 -0700, Sam Portolla wrote: > Yes, thanks I had looked at the kernel code and know how transmit > timeouts come to be in normal cases. The driver specifies a timeout > period to the network layer, along with a callback function to call in > case of Tx timeout so the driver can do error handling which is > typically to reset the driver (and this happened in the case of the > BNX2 linux driver our system uses as well). Above I had asked some > specific questions with regards to whether a known bug w/ qdisc could > stop the Tx Q's to the device and thereby cause traffic timeouts. Also > it seems from the email thread on the patch I had mentioned above that > the qdisc issue can cause memory corruption, which could then tie it > in with the BUG_ON in exit_mmap() which Hugh had previously commented > on. I am hoping the engineers who fixed the QDISC issue can comment on > the former and Hugh can comment on the BUG_ON again. Regards. The commit you mention is about a very unusual use of qdiscs. I really doubt it is your problem. Most advanced tc users probably wont stick with 2.6.23 kernels. Please post : tc -s -d qdisc And for all your network devices : for DEV in eth0 eth1 eth2 do tc -s -d class show dev $DEV done