From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752176AbbE1CWa (ORCPT ); Wed, 27 May 2015 22:22:30 -0400 Received: from ozlabs.org ([103.22.144.67]:49415 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750812AbbE1CWX (ORCPT ); Wed, 27 May 2015 22:22:23 -0400 From: Rusty Russell To: Peter Zijlstra Cc: mingo@kernel.org, mathieu.desnoyers@efficios.com, oleg@redhat.com, paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, andi@firstfloor.org, rostedt@goodmis.org, tglx@linutronix.de, laijs@cn.fujitsu.com, linux@horizon.com Subject: Re: [PATCH v5 00/10] latched RB-trees and __module_address() In-Reply-To: <20150414064149.GM23123@twins.programming.kicks-ass.net> References: <20150413141126.756350256@infradead.org> <87wq1fs9ha.fsf@rustcorp.com.au> <20150414064149.GM23123@twins.programming.kicks-ass.net> User-Agent: Notmuch/0.17 (http://notmuchmail.org) Emacs/24.4.1 (x86_64-pc-linux-gnu) Date: Thu, 28 May 2015 11:37:17 +0930 Message-ID: <87zj4pwj3e.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > On Tue, Apr 14, 2015 at 12:27:05PM +0930, Rusty Russell wrote: Hmm, this blows up: > +static void module_assert_mutex_or_preempt(void) > +{ > +#ifdef CONFIG_LOCKDEP > + if (!unlikely(debug_locks)) > + return; > + > + WARN_ON(!rcu_held_lock_sched_held() && > + !lockdep_is_held(&module_mutex)); That's rcu_read_lock_sched_held, not rcu_held_lock_sched_held(). Also, your unlikely is weird and backwards. I changed it as below, and folded. It's in modules-next. I'm now going to do some *actual* testing, and I'll go all Torvalds on you if this spews warnings... Cheers, Rusty. diff --git a/kernel/module.c b/kernel/module.c index 4a89b88b4428..a15899e00ca9 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -113,10 +113,10 @@ static void module_assert_mutex(void) static void module_assert_mutex_or_preempt(void) { #ifdef CONFIG_LOCKDEP - if (!unlikely(debug_locks)) + if (unlikely(!debug_locks)) return; - WARN_ON(!rcu_held_lock_sched_held() && + WARN_ON(!rcu_read_lock_sched_held() && !lockdep_is_held(&module_mutex)); #endif }