From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753478Ab0C2PJv (ORCPT ); Mon, 29 Mar 2010 11:09:51 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:39701 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753348Ab0C2PJu (ORCPT ); Mon, 29 Mar 2010 11:09:50 -0400 Date: Mon, 29 Mar 2010 08:09:46 -0700 From: "Paul E. McKenney" To: Tilman Schmidt Cc: linux-kernel@vger.kernel.org Subject: Re: CONFIG_PROVE_RCU breaks proprietary modules (rcu_lock_map) Message-ID: <20100329150946.GB2569@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <4BA689EA.4050102@imap.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4BA689EA.4050102@imap.cc> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 21, 2010 at 10:04:42PM +0100, Tilman Schmidt wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > I know there's not much sympathy for troubles with proprietary modules > here, but the following might save some trouble to kernel developers as > well as users forced to resort to proprietary drivers: > > Setting the kernel configuration option PROVE_RCU creates a reference to > the GPL-exported global variable rcu_lock_map even in modules that do > not use RCU. In the case of non-GPL modules, this leads to a build > failure because of the license incompatibility. > (I did not find out where that reference comes from.) > > So if building a proprietary module fails with the message: > > FATAL: modpost: GPL-incompatible module uses GPL-only symbol > 'rcu_lock_map' > > try rebuilding your kernel with the PROVE_RCU option disabled. > > Hope it helps someone. I am comfortable with PROVE_RCU being incompatible with non-GPL modules. After all, it is only a debugging option, not intended for production use. Thanx, Paul