From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932421Ab3CLJqb (ORCPT ); Tue, 12 Mar 2013 05:46:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63894 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754946Ab3CLJq3 (ORCPT ); Tue, 12 Mar 2013 05:46:29 -0400 Subject: Re: rcu: fix hlist_bl_set_first_rcu annotation From: Steven Whitehouse To: paulmck@linux.vnet.ibm.com Cc: Dipankar Sarma , linux-kernel@vger.kernel.org, adas@redhat.com, hch@lst.de, npiggin@gmail.com In-Reply-To: <20130203183958.GO2632@linux.vnet.ibm.com> References: <1359572877.2719.50.camel@menhir> <20130203183958.GO2632@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Organization: Red Hat UK Ltd Date: Tue, 12 Mar 2013 09:44:29 +0000 Message-ID: <1363081470.2732.1.camel@menhir> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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, 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); > > } > > > > /** > > > > >