1 files changed, 13 insertions, 7 deletions

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 2ff1b9499568..9604b91902b8 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -18,6 +18,7 @@ struct mptcp_pm_add_entry {
 	u8			retrans_times;
 	struct timer_list	add_timer;
 	struct mptcp_sock	*sock;
+	struct rcu_head		rcu;
 };
 
 static DEFINE_SPINLOCK(mptcp_pm_list_lock);
@@ -155,7 +156,7 @@ bool mptcp_remove_anno_list_by_saddr(struct mptcp_sock *msk,
 
 	entry = mptcp_pm_del_add_timer(msk, addr, false);
 	ret = entry;
-	kfree(entry);
+	kfree_rcu(entry, rcu);
 
 	return ret;
 }
@@ -345,22 +346,27 @@ mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 {
 	struct mptcp_pm_add_entry *entry;
 	struct sock *sk = (struct sock *)msk;
-	struct timer_list *add_timer = NULL;
+	bool stop_timer = false;
+
+	rcu_read_lock();
 
 	spin_lock_bh(&msk->pm.lock);
 	entry = mptcp_lookup_anno_list_by_saddr(msk, addr);
 	if (entry && (!check_id || entry->addr.id == addr->id)) {
 		entry->retrans_times = ADD_ADDR_RETRANS_MAX;
-		add_timer = &entry->add_timer;
+		stop_timer = true;
 	}
 	if (!check_id && entry)
 		list_del(&entry->list);
 	spin_unlock_bh(&msk->pm.lock);
 
-	/* no lock, because sk_stop_timer_sync() is calling timer_delete_sync() */
-	if (add_timer)
-		sk_stop_timer_sync(sk, add_timer);
+	/* Note: entry might have been removed by another thread.
+	 * We hold rcu_read_lock() to ensure it is not freed under us.
+	 */
+	if (stop_timer)
+		sk_stop_timer_sync(sk, &entry->add_timer);
 
+	rcu_read_unlock();
 	return entry;
 }
 
@@ -415,7 +421,7 @@ static void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
 
 	list_for_each_entry_safe(entry, tmp, &free_list, list) {
 		sk_stop_timer_sync(sk, &entry->add_timer);
-		kfree(entry);
+		kfree_rcu(entry, rcu);
 	}
 }