diff --git a/lib/idr.c b/lib/idr.c
index e2adc457abb4..457430cff8c5 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -40,6 +40,8 @@ int idr_alloc_u32(struct idr *idr, void *ptr, u32 *nextid,
 
 	if (WARN_ON_ONCE(!(idr->idr_rt.xa_flags & ROOT_IS_IDR)))
 		idr->idr_rt.xa_flags |= IDR_RT_MARKER;
+	if (max < base)
+		return -ENOSPC;
 
 	id = (id < base) ? 0 : id - base;
 	radix_tree_iter_init(&iter, id);
diff --git a/tools/testing/radix-tree/idr-test.c b/tools/testing/radix-tree/idr-test.c
index 2f830ff8396c..945144e98507 100644
--- a/tools/testing/radix-tree/idr-test.c
+++ b/tools/testing/radix-tree/idr-test.c
@@ -57,6 +57,26 @@ void idr_alloc_test(void)
 	idr_destroy(&idr);
 }
 
+void idr_alloc2_test(void)
+{
+	int id;
+	struct idr idr = IDR_INIT_BASE(idr, 1);
+
+	id = idr_alloc(&idr, idr_alloc2_test, 0, 1, GFP_KERNEL);
+	assert(id == -ENOSPC);
+
+	id = idr_alloc(&idr, idr_alloc2_test, 1, 2, GFP_KERNEL);
+	assert(id == 1);
+
+	id = idr_alloc(&idr, idr_alloc2_test, 0, 1, GFP_KERNEL);
+	assert(id == -ENOSPC);
+
+	id = idr_alloc(&idr, idr_alloc2_test, 0, 2, GFP_KERNEL);
+	assert(id == -ENOSPC);
+
+	idr_destroy(&idr);
+}
+
 void idr_replace_test(void)
 {
 	DEFINE_IDR(idr);
@@ -409,6 +429,7 @@ void idr_checks(void)
 
 	idr_replace_test();
 	idr_alloc_test();
+	idr_alloc2_test();
 	idr_null_test();
 	idr_nowait_test();
 	idr_get_next_test(0);