diff --git a/repos/base/src/core/region_map_component.cc b/repos/base/src/core/region_map_component.cc
index dfbd48b802..3932176c82 100644
--- a/repos/base/src/core/region_map_component.cc
+++ b/repos/base/src/core/region_map_component.cc
@@ -512,8 +512,13 @@ void Region_map_component::detach(Local_addr local_addr)
 		        "the beginning of the region ", Hex(region_ptr->base()));
 
 	Dataspace_component *dsc = region_ptr->dataspace();
-	if (!dsc && _diag.enabled)
-		warning("detach: region of ", this, " may be inconsistent!");
+
+	if (!dsc) {
+		if (_diag.enabled)
+			warning("detach: region of ", this, " may be inconsistent!");
+		return;
+	}
+
 
 	/* inform dataspace about detachment */
 	dsc->detached_from(region_ptr);
diff --git a/repos/base/src/lib/base/avl_tree.cc b/repos/base/src/lib/base/avl_tree.cc
index 2a76b03f58..16b2341d8d 100644
--- a/repos/base/src/lib/base/avl_tree.cc
+++ b/repos/base/src/lib/base/avl_tree.cc
@@ -49,6 +49,11 @@ void Avl_node_base::_rotate_subtree(Avl_node_base *node, Side side, Policy &poli
 	Avl_node_base *node_r   = node->_child[!side];
 	Avl_node_base *node_r_l = node_r->_child[side];
 
+	if (!node_r) {
+		error("avl rotation node_r is invalid");
+		return;
+	}
+
 	/* simple rotation */
 	if (node_r->_bias() == !side) {
 
diff --git a/repos/base/src/lib/base/lock.cc b/repos/base/src/lib/base/lock.cc
index 4c67500cb3..76536664b8 100644
--- a/repos/base/src/lib/base/lock.cc
+++ b/repos/base/src/lib/base/lock.cc
@@ -98,7 +98,8 @@ void Cancelable_lock::lock()
 		if (!applicants)
 			_last_applicant = &myself;
 	} else {
-		_last_applicant->applicant_to_wake_up(&myself);
+		if (_last_applicant)
+			_last_applicant->applicant_to_wake_up(&myself);
 		_last_applicant = &myself;
 	}