From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?Q3Jpc3RpYW4gUm9kcsOtZ3Vleg==?= Subject: Re: BUG: soft lockup - CPU#6 stuck for 22s! [httpd2-event:15597] Date: Wed, 29 Aug 2012 23:05:10 -0400 Message-ID: <503ED866.3020609@opensuse.org> References: <5038215E.60403@opensuse.org> <1345885186.19483.109.camel@edumazet-glaptop> <1345886085.19483.141.camel@edumazet-glaptop> <1345895225.19483.447.camel@edumazet-glaptop> <1346040367.2420.22.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Netdev , Yuchung Cheng , Eric Dumazet To: Neal Cardwell Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:63843 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754024Ab2H3DGe (ORCPT ); Wed, 29 Aug 2012 23:06:34 -0400 Received: by ialo24 with SMTP id o24so2457325ial.19 for ; Wed, 29 Aug 2012 20:06:33 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: El mi=C3=A9 29 ago 2012 21:37:46 CLT, Neal Cardwell escribi=C3=B3: Hi neal, thanks for taking a look at this.. > 1) Are you still seeing this problem in your workload? If so, would > you have time to try another small patch to add instrumentation to > track down the cause? After Eric's patch I no longer see this backtrace or hang, however the=20 machine does hang apparently for another reason that I have been unable to capture no clue at all in the logs and the KVM-over-ip video does not respond=20 after hang, needing a reset, that's strange though, as it is usually able to display kernel messages= =20 after a crash. > 2) Do you happen to run with the tcp_mtu_probing sysctl enabled? No, sysctl returns : net.ipv4.tcp_mtu_probing =3D 0