--- x/kernel/rcu/tree.c
+++ y/kernel/rcu/tree.c
@@ -2957,7 +2957,8 @@ krc_this_cpu_lock(unsigned long *flags)
 
 	local_irq_save(*flags);	// For safely calling this_cpu_ptr().
 	krcp = this_cpu_ptr(&krc);
-	raw_spin_lock(&krcp->lock);
+	while (!raw_spin_trylock(&krcp->lock))
+		;
 
 	return krcp;
 }
--- x/kernel/bpf/lpm_trie.c
+++ y/kernel/bpf/lpm_trie.c
@@ -382,9 +382,10 @@ static long trie_update_elem(struct bpf_
 			trie->n_entries--;
 
 		rcu_assign_pointer(*slot, new_node);
-		kfree_rcu(node, rcu);
 
-		goto out;
+		spin_unlock_irqrestore(&trie->lock, irq_flags);
+		kfree_rcu(node, rcu);
+		return 0;
 	}
 
 	/* If the new node matches the prefix completely, it must be inserted