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-rw-r--r--net/ipv4/inet_hashtables.c17
-rw-r--r--net/ipv4/inet_timewait_sock.c8
2 files changed, 19 insertions, 6 deletions
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 24a38b56fab9..f58d73888638 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -650,8 +650,20 @@ bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk)
spin_lock(lock);
if (osk) {
WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
- ret = sk_nulls_del_node_init_rcu(osk);
- } else if (found_dup_sk) {
+ ret = sk_hashed(osk);
+ if (ret) {
+ /* Before deleting the node, we insert a new one to make
+ * sure that the look-up-sk process would not miss either
+ * of them and that at least one node would exist in ehash
+ * table all the time. Otherwise there's a tiny chance
+ * that lookup process could find nothing in ehash table.
+ */
+ __sk_nulls_add_node_tail_rcu(sk, list);
+ sk_nulls_del_node_init_rcu(osk);
+ }
+ goto unlock;
+ }
+ if (found_dup_sk) {
*found_dup_sk = inet_ehash_lookup_by_sk(sk, list);
if (*found_dup_sk)
ret = false;
@@ -660,6 +672,7 @@ bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk)
if (ret)
__sk_nulls_add_node_rcu(sk, list);
+unlock:
spin_unlock(lock);
return ret;
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 1d77d992e6e7..beed32fff484 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -91,10 +91,10 @@ void inet_twsk_put(struct inet_timewait_sock *tw)
}
EXPORT_SYMBOL_GPL(inet_twsk_put);
-static void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
- struct hlist_nulls_head *list)
+static void inet_twsk_add_node_tail_rcu(struct inet_timewait_sock *tw,
+ struct hlist_nulls_head *list)
{
- hlist_nulls_add_head_rcu(&tw->tw_node, list);
+ hlist_nulls_add_tail_rcu(&tw->tw_node, list);
}
static void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
@@ -147,7 +147,7 @@ void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
spin_lock(lock);
- inet_twsk_add_node_rcu(tw, &ehead->chain);
+ inet_twsk_add_node_tail_rcu(tw, &ehead->chain);
/* Step 3: Remove SK from hash chain */
if (__sk_nulls_del_node_init_rcu(sk))