From ed86308f6179d8fa6151c2d0f652aad0091548e2 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Fri, 9 Apr 2010 16:42:15 +0200 Subject: [PATCH] netfilter: remove invalid rcu_dereference() calls The CONFIG_PROVE_RCU option discovered a few invalid uses of rcu_dereference() in netfilter. In all these cases, the code code intends to check whether a pointer is already assigned when performing registration or whether the assigned pointer matches when performing unregistration. The entire registration/ unregistration is protected by a mutex, so we don't need the rcu_dereference() calls. Reported-by: Valdis Kletnieks Tested-by: Valdis Kletnieks Signed-off-by: Patrick McHardy --- net/netfilter/nf_conntrack_ecache.c | 18 ++++-------------- net/netfilter/nf_log.c | 8 ++------ 2 files changed, 6 insertions(+), 20 deletions(-) diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c index d5a9bcd7d61b..849614af2322 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 015725a5cd50..908f59935fbb 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]); } -- 2.20.1