From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755345Ab3CLMre (ORCPT ); Tue, 12 Mar 2013 08:47:34 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:59136 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755127Ab3CLMrc (ORCPT ); Tue, 12 Mar 2013 08:47:32 -0400 Date: Tue, 12 Mar 2013 05:46:48 -0700 From: "Paul E. McKenney" To: Steven Whitehouse Cc: Dipankar Sarma , linux-kernel@vger.kernel.org, adas@redhat.com, hch@lst.de, npiggin@gmail.com Subject: Re: rcu: fix hlist_bl_set_first_rcu annotation Message-ID: <20130312124648.GC3725@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1359572877.2719.50.camel@menhir> <20130203183958.GO2632@linux.vnet.ibm.com> <1363081470.2732.1.camel@menhir> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1363081470.2732.1.camel@menhir> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13031212-7408-0000-0000-00000DB785C8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 12, 2013 at 09:44:29AM +0000, Steven Whitehouse wrote: > Hi, > > On Sun, 2013-02-03 at 10:39 -0800, Paul E. McKenney wrote: > > On Wed, Jan 30, 2013 at 07:07:57PM +0000, Steven Whitehouse wrote: > > > > > > Abhi noticed that we were getting a complaint from the RCU subsystem > > > about access of an RCU protected list under the write side bit lock. > > > This patch adds additional annotation to check both the RCU read > > > lock and the write side bit lock before printing a message. > > > > > > Signed-off-by: Steven Whitehouse > > > Reported-by: Abhijith Das > > > Tested-by: Abhijith Das > > > > Looks plausible to me on first glance, copying Nick Piggin and Christoph > > Hellwig. If they have no objections, I will queue this. > > > > Thanx, Paul > > > > Just a quick query to see what happened to this patch... it doesn't > appear to have landed in Linus' tree yet, and I can't spot it in your > git trees at korg either, Hello, Steve, I have queued it for 3.10, and will push it to -rcu shortly. Thanx, Paul > Steve. > > > > > diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h > > > index 31f9d75..2eb8855 100644 > > > --- a/include/linux/list_bl.h > > > +++ b/include/linux/list_bl.h > > > @@ -125,6 +125,11 @@ static inline void hlist_bl_unlock(struct hlist_bl_head *b) > > > __bit_spin_unlock(0, (unsigned long *)b); > > > } > > > > > > +static inline bool hlist_bl_is_locked(struct hlist_bl_head *b) > > > +{ > > > + return bit_spin_is_locked(0, (unsigned long *)b); > > > +} > > > + > > > /** > > > * hlist_bl_for_each_entry - iterate over list of given type > > > * @tpos: the type * to use as a loop cursor. > > > diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h > > > index cf1244f..4f216c5 100644 > > > --- a/include/linux/rculist_bl.h > > > +++ b/include/linux/rculist_bl.h > > > @@ -20,7 +20,7 @@ static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, > > > static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h) > > > { > > > return (struct hlist_bl_node *) > > > - ((unsigned long)rcu_dereference(h->first) & ~LIST_BL_LOCKMASK); > > > + ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK); > > > } > > > > > > /** > > > > > > > > > >