From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: Re: conntrack (possibly) hangs on our ARM CPU in case we delete 5k+ connections as fast as possible Date: Tue, 14 Mar 2017 11:33:00 +0100 Message-ID: <20170314103300.GA8738@breakpoint.cc> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netfilter-devel@vger.kernel.org To: Peter Marczis Return-path: Received: from Chamillionaire.breakpoint.cc ([146.0.238.67]:38402 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750771AbdCNKdT (ORCPT ); Tue, 14 Mar 2017 06:33:19 -0400 Content-Disposition: inline In-Reply-To: Sender: netfilter-devel-owner@vger.kernel.org List-ID: Peter Marczis wrote: > Hello developers, > I'm seeking some help to debug and solve one of my issues. > > We observed that if we create 30k connections, everything works as > expected, but when we start to disconnect them, > conntrack (well not confirmed yet fully) makes the kernel side busy, > and looks like no scheduling happens. What do you mean by 'disconnect'? conntrack -F ? My wild guss is you need to backport commit d93c6258ee4255749c10012c50a31c08f4e9fb16 netfilter: conntrack: resched in nf_ct_iterate_cleanup > The whole thing works as expected, the only problem it makes our > processes and well everything on user side hanging for a couple of > seconds 10-30s, > which of course triggers our HW Watchdog, and we end up in a reboot. You could try CONFIG_LOCKUP_DETECTOR=y CONFIG_HARDLOCKUP_DETECTOR=y