From: Patrick McHardy <kaber@xxxxxxxxx>
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 <Valdis.Kletnieks@xxxxxx>
Tested-by: Valdis Kletnieks <Valdis.Kletnieks@xxxxxx>
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
---
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 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]);
}
--
1.7.0.4
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