From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guillaume Nault Subject: Re: Fw: [Bug 111771] New: deadlock in ppp/l2tp Date: Thu, 4 Feb 2016 14:05:10 +0100 Message-ID: <20160204130510.GD1267@alphalink.fr> References: <20160203110431.7b878a4f@samsung9> <20160203171401.GC1267@alphalink.fr> <56B2AA40.5090601@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, Stephen Hemminger To: Sorin Manolache Return-path: Received: from zimbra.alphalink.fr ([217.15.80.77]:56416 "EHLO zimbra.alphalink.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933339AbcBDNFN (ORCPT ); Thu, 4 Feb 2016 08:05:13 -0500 Content-Disposition: inline In-Reply-To: <56B2AA40.5090601@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Feb 04, 2016 at 02:32:48AM +0100, Sorin Manolache wrote: > On 2016-02-03 18:14, Guillaume Nault wrote: > > > >Sorin, it seems like one of your L2TP tunnels is routed to one of its upper PPP > >devices. Most likely, the peer address of the PPP device is also the address of > >the remote L2TP tunnel endpoint. So L2TP packets are sent back to the upper PPP > >device, instead of leaving through the physical interface. > > Thank you. You are right. There's a host route to the peer over the ppp0 > interface in the routing table. I don't know how it gets there. I've checked > the source code of pppd and no such route is added for kernels newer than > 2.1.16. I've grepped /etc for "route" in order to detect a "post-up" script > that would add that route. Nothing. I've double-checked by executing strace > on xl2tpd and its children (i.e. pppd and the initialisation scripts) and I > couldn't find any ioctl SIOCADDRT. So it's a total mystery for me where that > route comes from. Could it come from the kernel? > If that's a /32 IPv4 route to the peer address of the PPP link and has the "proto kernel" attribute, then yes, that's most likely the one generated by the kernel.