From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [Patch net-next] vxlan: do real refcnt for vn_sock Date: Thu, 30 May 2013 20:56:18 -0700 Message-ID: <20130530205618.0d3a8d16@nehalam.linuxnetplumber.net> References: <1369739242-5944-1-git-send-email-amwang@redhat.com> <20130528214142.4e41db6f@nehalam.linuxnetplumber.net> <1369816780.12227.21.camel@cr0> <1369968945.5304.1.camel@cr0> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, "David S. Miller" To: Cong Wang Return-path: Received: from mail-pb0-f41.google.com ([209.85.160.41]:57840 "EHLO mail-pb0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750825Ab3EaD4X (ORCPT ); Thu, 30 May 2013 23:56:23 -0400 Received: by mail-pb0-f41.google.com with SMTP id xb12so1514007pbc.28 for ; Thu, 30 May 2013 20:56:23 -0700 (PDT) In-Reply-To: <1369968945.5304.1.camel@cr0> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 31 May 2013 10:55:45 +0800 Cong Wang wrote: > On Wed, 2013-05-29 at 16:39 +0800, Cong Wang wrote: > > On Tue, 2013-05-28 at 21:41 -0700, Stephen Hemminger wrote: > > > Why not just fix the requirement to drop rtnl when calling igmp. > > > The code comes out cleaner and safer as well. > > > > Besides you forget to lock the socket before calling _ip_mc_join_group() > > (and also the order is very important too), your patch doesn't fix the > > problem I met. The full backtrace is below: > > > > Hi, Stephen, > > Do you think my patch is an easier solution? It at least fixes the > crash, while your patch doesn't. :) > > No. your patch doesn't fix the real problem. The real fix is more complex because of how socket locking interacts with RTNL. I have been busy with health stuff, so the going is slow.