From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?q?R=E9mi_Denis-Courmont?= Subject: Re: [Bugme-new] [Bug 11469] New: TUN with 1024 neighbours: ip6_dst_lookup_tail NULL crash Date: Sun, 7 Sep 2008 21:19:49 +0300 Message-ID: <200809072119.50307.rdenis@simphalempin.com> References: <20080831111304.d57b9f5a.akpm@linux-foundation.org> <20080907181109.GA2466@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Andrew Morton , netdev@vger.kernel.org, bugme-daemon@bugzilla.kernel.org To: Evgeniy Polyakov Return-path: Received: from yop.chewa.net ([91.121.105.214]:39822 "EHLO yop.chewa.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754138AbYIGSTy convert rfc822-to-8bit (ORCPT ); Sun, 7 Sep 2008 14:19:54 -0400 In-Reply-To: <20080907181109.GA2466@2ka.mipt.ru> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Le dimanche 7 septembre 2008 21:11:09 Evgeniy Polyakov, vous avez =E9cr= it=A0: > Since dst entry is allowed not to have neighbour entry, flush it just > like with incomplete one. This drops performance of your application > with more than 1024 neighbours to 1024 messages, to fix it you should > tune ipv6 routing parameters (gc intervals, gc threshold, maximum num= ber > of entries and so on). There may be another problem with perfomance > though, at least I was able to bump it 10 times with different settin= gs, > but still two times smaller than with 4k neighbours. That looks like a trivial local DoS against the IPv6 stack though? Especially in the case that the interface has IFF_NOARP, that seems lik= e a=20 weird limitation. Oh well... --=20 R=E9mi Denis-Courmont http://www.remlab.net/