From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [Bugme-new] [Bug 10326] New: inconsistent lock state in net_rx_action Date: Thu, 27 Mar 2008 09:55:42 +0100 Message-ID: <20080327085542.GA2778@ami.dom.local> References: <20080325134320.21525479.akpm@linux-foundation.org> <47EAD8A5.3070806@gmail.com> <20080326171403.ad186037.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, bugme-daemon@bugzilla.kernel.org, marcus@better.se, Stephen Hemminger , "Rafael J. Wysocki" , LKML To: Andrew Morton Return-path: Received: from wr-out-0506.google.com ([64.233.184.227]:13965 "EHLO wr-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754830AbYC0Ivi (ORCPT ); Thu, 27 Mar 2008 04:51:38 -0400 Received: by wr-out-0506.google.com with SMTP id c48so3214386wra.1 for ; Thu, 27 Mar 2008 01:51:37 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20080326171403.ad186037.akpm@linux-foundation.org> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Mar 26, 2008 at 05:14:03PM -0700, Andrew Morton wrote: ... > > >> http://bugzilla.kernel.org/show_bug.cgi?id=10326 ... > No, it's not an irq_disable() thing, directly. > > What lockdep is saying is that sky2_poll() is taking napi->poll_lock for > writing with softirqs enabled, but net_rx_action() takes the same lock from > within softirq context. > > If sky2_poll() always takes napi->poll_lock under local_irq_disable() then > that would be a lockdep bug. sky2_poll() doesn't take napi->poll_lock; this lock is taken by netpoll_poll() before calling sky2_poll(). And before this hardirqs are disabled in write_msg(). So, theoretically lockdep could be right if sky2_poll() would enable irqs after this. (If it were done in netpoll - lockdep should warn before or after sky2_poll() call.) But I really can't see any such possibility in sky2_poll(). Regards, Jarek P.