From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: Re: crash on >= 4.9.0 kernel seems nf related Date: Mon, 26 Jun 2017 15:16:32 +0200 Message-ID: <20170626131632.GI29636@breakpoint.cc> References: <20170516082128.GB16290@breakpoint.cc> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 8bit Cc: Florian Westphal , Pablo Neira Ayuso , netfilter-devel@vger.kernel.org To: =?iso-8859-15?Q?Bj=F8rnar?= Ness Return-path: Received: from Chamillionaire.breakpoint.cc ([146.0.238.67]:49800 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751410AbdFZNRc (ORCPT ); Mon, 26 Jun 2017 09:17:32 -0400 Content-Disposition: inline In-Reply-To: Sender: netfilter-devel-owner@vger.kernel.org List-ID: Bjørnar Ness wrote: > When trying to narrow down the problem, I removed the NAT rules, and > in particular > the > > chain postrouting { > type nat hook postrouting priority 100 > } > > And the problem disappears. Commenting in the above block again, > causes the following to happen: > > kworker/0:0 starts to use more and more cpu, and in less than a minute > renders the > machine useless. If network cable is unplugged, it takes aroung 30 > seconds for the machine to get into a useful state again. The kworker is most likely the conntrack gc worker, but the gc worker is nat agnostic, so I don't see how this makes a difference wrt. nat postrouting hook presence. perf top might help pinpoint the source. What kernel is this, exactly? 4.10 (and 4.9.14 and later) has a change to make gc worker use less cycles. But I don't see the NAT connection.