Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932695Ab0DHPgN (ORCPT ); Thu, 8 Apr 2010 11:36:13 -0400 Received: from stinky.trash.net ([213.144.137.162]:39412 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932655Ab0DHPgL (ORCPT ); Thu, 8 Apr 2010 11:36:11 -0400 Message-ID: <4BBDF7E7.708@trash.net> Date: Thu, 08 Apr 2010 17:36:07 +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> <4BBDC0CC.7080305@trash.net> <6795.1270740197@localhost> In-Reply-To: <6795.1270740197@localhost> X-Enigmail-Version: 0.95.0 Content-Type: multipart/mixed; boundary="------------030403000004010505030202" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5198 Lines: 147 This is a multi-part message in MIME format. --------------030403000004010505030202 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Valdis.Kletnieks@vt.edu wrote: > On Thu, 08 Apr 2010 13:41:00 +0200, Patrick McHardy said: >>> [ 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] >> There are some unnecessary rcu_dereference() calls in the conntrack >> notifier registration and unregistration functions. >> >> Does this fix it? > > Well, it *changed* it. Does the rcu_defererence_check() only fire on the > first time it hits something, so we've fixed the first one and now we get to > see the second one? It appears that way, otherwise you should have seen a second warning in nf_conntrack_ecache the last time. > (For what it's worth, if this is going to be one-at-a-time whack-a-mole, I'm > OK on that, just want to know up front.) I went through the other files and I believe this should be it. We already removed most of these incorrect rcu_dereference() calls a while back. > [ 9.299425] ip_tables: (C) 2000-2006 Netfilter Core Team > [ 9.299486] > [ 9.299486] =================================================== > [ 9.300499] [ INFO: suspicious rcu_dereference_check() usage. ] > [ 9.301001] --------------------------------------------------- > [ 9.301523] net/netfilter/nf_log.c:55 invoked rcu_dereference_check() without protection! > [ 9.302066] --------------030403000004010505030202 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); } diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c index 015725a..908f599 100644 --- a/net/netfilter/nf_log.c +++ b/net/netfilter/nf_log.c @@ -35,7 +35,6 @@ static struct nf_logger *__find_logger(int pf, const char *str_logger) /* return EEXIST if the same logger is registred, 0 on success. */ int nf_log_register(u_int8_t pf, struct nf_logger *logger) { - const struct nf_logger *llog; int i; if (pf >= ARRAY_SIZE(nf_loggers)) @@ -52,8 +51,7 @@ int nf_log_register(u_int8_t pf, struct nf_logger *logger) } else { /* register at end of list to honor first register win */ list_add_tail(&logger->list[pf], &nf_loggers_l[pf]); - llog = rcu_dereference(nf_loggers[pf]); - if (llog == NULL) + if (nf_loggers[pf] == NULL) rcu_assign_pointer(nf_loggers[pf], logger); } @@ -65,13 +63,11 @@ EXPORT_SYMBOL(nf_log_register); void nf_log_unregister(struct nf_logger *logger) { - const struct nf_logger *c_logger; int i; mutex_lock(&nf_log_mutex); for (i = 0; i < ARRAY_SIZE(nf_loggers); i++) { - c_logger = rcu_dereference(nf_loggers[i]); - if (c_logger == logger) + if (nf_loggers[i] == logger) rcu_assign_pointer(nf_loggers[i], NULL); list_del(&logger->list[i]); } --------------030403000004010505030202-- -- 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/