From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031735Ab2COQfU (ORCPT ); Thu, 15 Mar 2012 12:35:20 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:42802 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031620Ab2COQfQ (ORCPT ); Thu, 15 Mar 2012 12:35:16 -0400 Date: Thu, 15 Mar 2012 09:08:15 -0700 From: "Paul E. McKenney" To: Dave Jones , Linux Kernel Subject: Re: list-debug variants of rcu list routines. Message-ID: <20120315160815.GD2381@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20120315021738.GA31213@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120315021738.GA31213@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12031516-3270-0000-0000-000004D0B5E1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 14, 2012 at 10:17:39PM -0400, Dave Jones wrote: > * Make __list_add_rcu check the next->prev and prev->next pointers > just like __list_add does. > * Make list_del_rcu use __list_del_entry, which does the same checking > at deletion time. > > Has been running for a week here without anything being tripped up, > but it seems worth adding for completeness just in case something > ever does corrupt those lists. Queued, thank you! Thanx, Paul > Signed-off-by: Dave Jones > > diff -durpN '--exclude-from=/home/davej/.exclude' -u src/git-trees/kernel/linux/include/linux/rculist.h linux-dj/include/linux/rculist.h > --- src/git-trees/kernel/linux/include/linux/rculist.h 2011-07-23 00:05:34.000000000 -0400 > +++ linux-dj/include/linux/rculist.h 2012-03-07 00:21:47.050583527 -0500 > @@ -30,6 +30,7 @@ > * This is only for internal list manipulation where we know > * the prev/next entries already! > */ > +#ifndef CONFIG_DEBUG_LIST > static inline void __list_add_rcu(struct list_head *new, > struct list_head *prev, struct list_head *next) > { > @@ -38,6 +39,10 @@ static inline void __list_add_rcu(struct > rcu_assign_pointer(list_next_rcu(prev), new); > next->prev = new; > } > +#else > +extern void __list_add_rcu(struct list_head *new, > + struct list_head *prev, struct list_head *next); > +#endif > > /** > * list_add_rcu - add a new entry to rcu-protected list > @@ -108,7 +113,7 @@ static inline void list_add_tail_rcu(str > */ > static inline void list_del_rcu(struct list_head *entry) > { > - __list_del(entry->prev, entry->next); > + __list_del_entry(entry); > entry->prev = LIST_POISON2; > } > > diff -durpN '--exclude-from=/home/davej/.exclude' -u src/git-trees/kernel/linux/lib/list_debug.c linux-dj/lib/list_debug.c > --- src/git-trees/kernel/linux/lib/list_debug.c 2011-02-19 12:00:40.000000000 -0500 > +++ linux-dj/lib/list_debug.c 2012-03-07 00:18:12.108062540 -0500 > @@ -8,6 +8,7 @@ > > #include > #include > +#include > > /* > * Insert a new entry between two known consecutive entries. > @@ -73,3 +74,24 @@ void list_del(struct list_head *entry) > entry->prev = LIST_POISON2; > } > EXPORT_SYMBOL(list_del); > + > +/* > + * RCU variants. > + */ > +void __list_add_rcu(struct list_head *new, > + struct list_head *prev, struct list_head *next) > +{ > + WARN(next->prev != prev, > + "list_add_rcu corruption. next->prev should be " > + "prev (%p), but was %p. (next=%p).\n", > + prev, next->prev, next); > + WARN(prev->next != next, > + "list_add_rcu corruption. prev->next should be " > + "next (%p), but was %p. (prev=%p).\n", > + next, prev->next, prev); > + new->next = next; > + new->prev = prev; > + rcu_assign_pointer(list_next_rcu(prev), new); > + next->prev = new; > +} > +EXPORT_SYMBOL(__list_add_rcu); >