From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: [PATCH v2] ipv6: Don't depend on per socket memory for neighbour discovery messages Date: Tue, 3 Sep 2013 19:23:48 +0100 Message-ID: <20130903182348.GB4166@casper.infradead.org> References: <52261A12.3060203@wwwdotorg.org> <20130903172736.GB21729@order.stressinduktion.org> <52261F68.70907@wwwdotorg.org> <1378230697.7360.38.camel@edumazet-glaptop> <52262462.80308@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Dumazet , davem@davemloft.net, netdev@vger.kernel.org, Fabio Estevam To: Stephen Warren Return-path: Received: from casper.infradead.org ([85.118.1.10]:42328 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754147Ab3ICSXu (ORCPT ); Tue, 3 Sep 2013 14:23:50 -0400 Content-Disposition: inline In-Reply-To: <52262462.80308@wwwdotorg.org> Sender: netdev-owner@vger.kernel.org List-ID: On 09/03/13 at 12:03pm, Stephen Warren wrote: > On 09/03/2013 11:51 AM, Eric Dumazet wrote: > > On Tue, 2013-09-03 at 11:42 -0600, Stephen Warren wrote: > > > >> I don't see any extra messages from PROVE_LOCKING related to networking. > >> There is a single extra message from inside the audio driver, but that's > >> not networking-related at all. > > > > LOCKDEP is automatically disabled at first splat. > > > > Please try a kernel without audio driver ;) > > Ah, OK. Now I do see something from ipv6: > > > [ 25.327622] > > [ 25.329142] ============================================= > > [ 25.334533] [ INFO: possible recursive locking detected ] > > [ 25.339927] 3.11.0-rc7-next-20130830-00024-g209b4d8-dirty #17 Not tainted > > [ 25.346705] --------------------------------------------- > > [ 25.352095] login/704 is trying to acquire lock: > > [ 25.356705] (&ndev->lock){++--..}, at: [] ipv6_chk_mcast_addr+0x5c/0x200 > > [ 25.364405] > > [ 25.364405] but task is already holding lock: > > [ 25.370230] (&ndev->lock){++--..}, at: [] addrconf_rs_timer+0x18/0x134 Real deadlock, we should not hold idev->lock for ndisc_send_rs(), we should drop the lock beforehand I guess. We also don't hold idev->lock if we send out the RS via addrconf_dad_completed(). I'm confused why lockdep would only trigger after my patch, the deadlock is unrelated.