From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756674AbYHNWPR (ORCPT ); Thu, 14 Aug 2008 18:15:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751767AbYHNWPB (ORCPT ); Thu, 14 Aug 2008 18:15:01 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:45954 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751714AbYHNWPA (ORCPT ); Thu, 14 Aug 2008 18:15:00 -0400 Date: Thu, 14 Aug 2008 15:15:02 -0700 (PDT) Message-Id: <20080814.151502.251134900.davem@davemloft.net> To: penberg@cs.helsinki.fi Cc: vegard.nossum@gmail.com, vegardno@ifi.uio.no, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jgarzik@pobox.com, adobriyan@gmail.com Subject: Re: [RFC][PATCH] netconsole: avoid deadlock on printk from driver code From: David Miller In-Reply-To: References: <20080813.033749.165504341.davem@davemloft.net> <84144f020808140628m31d6d099t1fecdb1701c0bbdc@mail.gmail.com> X-Mailer: Mew version 5.2 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pekka J Enberg Date: Thu, 14 Aug 2008 16:44:32 +0300 (EEST) > @@ -598,6 +598,7 @@ > > spinlock_t lock; > spinlock_t rx_lock; > + spinlock_t tx_lock; > > chip_t chipset; > u32 rx_config; Why create a special purpose lock when the generic networking already is taking a lock for you to proect the TX path? Furthermore, as I just described in another reply, netpoll already knows that it might need to trylock() attempt on this lock in order to avoid the very deadlocks this thread is about.