From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933103AbXCRUdG (ORCPT ); Sun, 18 Mar 2007 16:33:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933196AbXCRUdF (ORCPT ); Sun, 18 Mar 2007 16:33:05 -0400 Received: from ug-out-1314.google.com ([66.249.92.175]:23331 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933103AbXCRUdE (ORCPT ); Sun, 18 Mar 2007 16:33:04 -0400 Date: Sun, 18 Mar 2007 22:33:45 +0200 From: "Michael S. Tsirkin" To: Alexey Kuznetsov Cc: "Michael S. Tsirkin" , Linux Kernel Mailing List , netdev@vger.kernel.org, general@lists.openfabrics.org, Roland Dreier Subject: Re: dst_ifdown breaks infiniband? Message-ID: <20070318203345.GF11078@mellanox.co.il> Reply-To: "Michael S. Tsirkin" References: <20070318155532.GG7958@mellanox.co.il> <20070318191238.GA20518@ms2.inr.ac.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070318191238.GA20518@ms2.inr.ac.ru> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Quoting Alexey Kuznetsov : Subject: Re: dst_ifdown breaks infiniband? > > Can dst->neighbour be changed to point to NULL instead, and the neighbour > > released? > > It should be cleared and we should be sure it will not be destroyed > before quiescent state. > > Seems, this is the only correct solution, but to do this we have > to audit all the places where dst->neighbour is dereferenced for > RCU safety. > > Actually, it is very good you caught this eventually, the bug was > so _disgusting_ that it was "forgotten" all the time, waiting for > someone who will point out that the king is naked. :-) Actually that might not be too bad: $grep -rIi 'dst->neighbour' net/ | wc -l 36 I'll try to do it. -- MST