Valdis.Kletnieks@xxxxxx 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]
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]);
}
