diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c
index 35abcb1ec051..86f8195d8039 100644
--- a/block/keyslot-manager.c
+++ b/block/keyslot-manager.c
@@ -103,6 +103,13 @@ int blk_ksm_init(struct blk_keyslot_manager *ksm, unsigned int num_slots)
 	spin_lock_init(&ksm->idle_slots_lock);
 
 	slot_hashtable_size = roundup_pow_of_two(num_slots);
+	/*
+	 * hash_ptr() assumes bits != 0, so ensure the hash table has at least 2
+	 * buckets.  This only makes a difference when there is only 1 keyslot.
+	 */
+	if (slot_hashtable_size < 2)
+		slot_hashtable_size = 2;
+
 	ksm->log_slot_ht_size = ilog2(slot_hashtable_size);
 	ksm->slot_hashtable = kvmalloc_array(slot_hashtable_size,
 					     sizeof(ksm->slot_hashtable[0]),