Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758389Ab0DHLlH (ORCPT ); Thu, 8 Apr 2010 07:41:07 -0400 Received: from stinky.trash.net ([213.144.137.162]:35541 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752156Ab0DHLlC (ORCPT ); Thu, 8 Apr 2010 07:41:02 -0400 Message-ID: <4BBDC0CC.7080305@trash.net> Date: Thu, 08 Apr 2010 13:41:00 +0200 From: Patrick McHardy User-Agent: Mozilla-Thunderbird 2.0.0.22 (X11/20090701) MIME-Version: 1.0 To: Valdis.Kletnieks@vt.edu CC: Andrew Morton , Peter Zijlstra , Ingo Molnar , "David S. Miller" , linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: mmotm 2010-04-05-16-09 uploaded References: <201004052336.o35NaeSE015814@imap1.linux-foundation.org> <13074.1270663309@localhost> In-Reply-To: <13074.1270663309@localhost> X-Enigmail-Version: 0.95.0 Content-Type: multipart/mixed; boundary="------------030704070607030103010608" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3712 Lines: 106 This is a multi-part message in MIME format. --------------030704070607030103010608 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Valdis.Kletnieks@vt.edu wrote: > On Mon, 05 Apr 2010 16:09:45 PDT, akpm@linux-foundation.org said: >> The mm-of-the-moment snapshot 2010-04-05-16-09 has been uploaded to >> >> http://userweb.kernel.org/~akpm/mmotm/ > > Seen in dmesg, 2.6.34-rc2-mmotm0323 didn't do this. Tossing it at all the > likely suspects, hopefully somebody will recognize it and save me the > bisecting. ;) > > [ 11.488535] ctnetlink v0.93: registering with nfnetlink. > [ 11.488579] > [ 11.488579] =================================================== > [ 11.489529] [ INFO: suspicious rcu_dereference_check() usage. ] > [ 11.489988] --------------------------------------------------- > [ 11.490494] net/netfilter/nf_conntrack_ecache.c:88 invoked rcu_dereference_check() without protection! > [ 11.491024] > [ 11.491024] other info that might help us debug this: > [ 11.491025] > [ 11.492834] > [ 11.492835] rcu_scheduler_active = 1, debug_locks = 0 > [ 11.494124] 1 lock held by swapper/1: > [ 11.494776] #0: (nf_ct_ecache_mutex){+.+...}, at: [] nf_conntrack_register_notifier+0x1a/0x76 > [ 11.495505] There are some unnecessary rcu_dereference() calls in the conntrack notifier registration and unregistration functions. Does this fix it? --------------030704070607030103010608 Content-Type: text/plain; name="x" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="x" diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c index d5a9bcd..849614a 100644 --- a/net/netfilter/nf_conntrack_ecache.c +++ b/net/netfilter/nf_conntrack_ecache.c @@ -81,11 +81,9 @@ EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events); int nf_conntrack_register_notifier(struct nf_ct_event_notifier *new) { int ret = 0; - struct nf_ct_event_notifier *notify; mutex_lock(&nf_ct_ecache_mutex); - notify = rcu_dereference(nf_conntrack_event_cb); - if (notify != NULL) { + if (nf_conntrack_event_cb != NULL) { ret = -EBUSY; goto out_unlock; } @@ -101,11 +99,8 @@ EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier); void nf_conntrack_unregister_notifier(struct nf_ct_event_notifier *new) { - struct nf_ct_event_notifier *notify; - mutex_lock(&nf_ct_ecache_mutex); - notify = rcu_dereference(nf_conntrack_event_cb); - BUG_ON(notify != new); + BUG_ON(nf_conntrack_event_cb != new); rcu_assign_pointer(nf_conntrack_event_cb, NULL); mutex_unlock(&nf_ct_ecache_mutex); } @@ -114,11 +109,9 @@ EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier); int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *new) { int ret = 0; - struct nf_exp_event_notifier *notify; mutex_lock(&nf_ct_ecache_mutex); - notify = rcu_dereference(nf_expect_event_cb); - if (notify != NULL) { + if (nf_expect_event_cb != NULL) { ret = -EBUSY; goto out_unlock; } @@ -134,11 +127,8 @@ EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier); void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *new) { - struct nf_exp_event_notifier *notify; - mutex_lock(&nf_ct_ecache_mutex); - notify = rcu_dereference(nf_expect_event_cb); - BUG_ON(notify != new); + BUG_ON(nf_expect_event_cb != new); rcu_assign_pointer(nf_expect_event_cb, NULL); mutex_unlock(&nf_ct_ecache_mutex); } --------------030704070607030103010608-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/