From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755839Ab2FWULL (ORCPT ); Sat, 23 Jun 2012 16:11:11 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:52266 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754554Ab2FWULJ (ORCPT ); Sat, 23 Jun 2012 16:11:09 -0400 Date: Sat, 23 Jun 2012 13:11:03 -0700 From: "Paul E. McKenney" To: Fengguang Wu Cc: "linux-kernel@vger.kernel.org" Subject: Re: BUG: tracer_alloc_buffers returned with preemption imbalance Message-ID: <20120623201103.GK2516@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20120623101251.GA10162@localhost> <20120623170147.GI2516@linux.vnet.ibm.com> <20120623174830.GA5617@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120623174830.GA5617@localhost> User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12062320-7282-0000-0000-00000A3CAD5D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jun 24, 2012 at 01:48:30AM +0800, Fengguang Wu wrote: > > > static inline int rcu_blocking_is_gp(void) > > > { > > > might_sleep(); /* Check for RCU read-side critical section. */ > > > + preempt_disable(); > > > return num_online_cpus() <= 1; > > > + preempt_enable(); > > > } > > > > Thank you! I have no idea how a preempt_disable() causes that badness > > to happen, but this commit is not yet critically important, so I will > > drop it. > > preempt_enable() becomes dead code because of the return statement? > I wonder why gcc didn't issue a warning (or I failed to catch it)... Color me blind and stupid!!! Thank you, will fix. Thanx, Paul