From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [IPV4 3/5] fib_trie: dump doesnt use RCU Date: Wed, 23 Jan 2008 22:43:37 -0800 (PST) Message-ID: <20080123.224337.80401207.davem@davemloft.net> References: <20080123224858.918669715@linux-foundation.org> <20080123.205007.16809712.davem@davemloft.net> <47983304.3030309@trash.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: shemminger@linux-foundation.org, netdev@vger.kernel.org To: kaber@trash.net Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:38326 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751114AbYAXGn2 (ORCPT ); Thu, 24 Jan 2008 01:43:28 -0500 In-Reply-To: <47983304.3030309@trash.net> Sender: netdev-owner@vger.kernel.org List-ID: From: Patrick McHardy Date: Thu, 24 Jan 2008 07:41:08 +0100 > David Miller wrote: > > and nothing in that code path retakes the RTNL semaphore. > > Actually we're always holding the rtnl during dumps, nlk->cb_mutex points > to rtnl_mutex in case of rtnetlink. It used to be held only during the first > ->dump invocation and not on continuations, but I changed this a few > versions ago. My bad. Thanks for the correction Patrick. But continuations can occur on subsequent recvmsg() calls, does it return to userspace with the mutex held? If so I'm pretty sure that's not allowed.