From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH] pkt_sched: Destroy gen estimators under rtnl_lock(). Date: Thu, 21 Aug 2008 10:18:30 +0000 Message-ID: <20080821101830.GB3963@ff.dom.local> References: <20080819085504.GB29038@gondor.apana.org.au> <20080819091642.GI4376@ff.dom.local> <20080821100155.GA3621@ff.dom.local> <20080821.030523.205239441.davem@davemloft.net> <20080821101145.GA3963@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: herbert@gondor.apana.org.au, netdev@vger.kernel.org, denys@visp.net.lb To: David Miller Return-path: Received: from fk-out-0910.google.com ([209.85.128.190]:56009 "EHLO fk-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752692AbYHUKSh (ORCPT ); Thu, 21 Aug 2008 06:18:37 -0400 Received: by fk-out-0910.google.com with SMTP id 18so584670fkq.5 for ; Thu, 21 Aug 2008 03:18:35 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20080821101145.GA3963@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Aug 21, 2008 at 10:11:45AM +0000, Jarek Poplawski wrote: > On Thu, Aug 21, 2008 at 03:05:23AM -0700, David Miller wrote: > > From: Jarek Poplawski > > Date: Thu, 21 Aug 2008 10:01:55 +0000 > > > > > If we do this with child qdisc from qdisc_graft() it's without > > > deactivation. The rest of the tree can be dequeued in the meantime > > > and call qdisc_tree_decrease_qlen() (like hfsc, tbf, netem), which > > > uses qdisc_lookup() to access this list. We list_del() under rtnl > > > lock only, they lookup under sch_tree_lock(). Is it a bit unsafe > > > or I miss something? > > > > They hold RTNL as well. > > > > Remember, sch_tree_lock() uses qdisc_root_lock() which as I've > > told you at least twice now asserts that RTNL is held :-) > > Actually, I've called it wrong, they hold qdisc root lock, but they > certainly can't have rtnl_lock() at the moment! I mean here: hfsc_dequeue(), netem_dequeue() and tbf_dequeue(). Jarek P.