diff --git a/crypto/aead.c b/crypto/aead.c
index 7707d32..1699109 100644
--- a/crypto/aead.c
+++ b/crypto/aead.c
@@ -288,6 +288,9 @@ int aead_register_instance(struct crypto_template *tmpl,
 {
 	int err;
 
+	if (WARN_ON(!inst->free))
+		return -EINVAL;
+
 	err = aead_prepare_alg(&inst->alg);
 	if (err)
 		return err;
diff --git a/crypto/ahash.c b/crypto/ahash.c
index cd5d984..68a0f0c 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -656,6 +656,9 @@ int ahash_register_instance(struct crypto_template *tmpl,
 {
 	int err;
 
+	if (WARN_ON(!inst->free))
+		return -EINVAL;
+
 	err = ahash_prepare_alg(&inst->alg);
 	if (err)
 		return err;
diff --git a/crypto/akcipher.c b/crypto/akcipher.c
index eeed6c1..f866085 100644
--- a/crypto/akcipher.c
+++ b/crypto/akcipher.c
@@ -147,6 +147,8 @@ EXPORT_SYMBOL_GPL(crypto_unregister_akcipher);
 int akcipher_register_instance(struct crypto_template *tmpl,
 			       struct akcipher_instance *inst)
 {
+	if (WARN_ON(!inst->free))
+		return -EINVAL;
 	akcipher_prepare_alg(&inst->alg);
 	return crypto_register_instance(tmpl, akcipher_crypto_instance(inst));
 }
diff --git a/crypto/shash.c b/crypto/shash.c
index 70faf28..c075b26 100644
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -577,6 +577,9 @@ int shash_register_instance(struct crypto_template *tmpl,
 {
 	int err;
 
+	if (WARN_ON(!inst->free))
+		return -EINVAL;
+
 	err = shash_prepare_alg(&inst->alg);
 	if (err)
 		return err;
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index 42add1e..7221def 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -865,6 +865,9 @@ int skcipher_register_instance(struct crypto_template *tmpl,
 {
 	int err;
 
+	if (WARN_ON(!inst->free))
+		return -EINVAL;
+
 	err = skcipher_prepare_alg(&inst->alg);
 	if (err)
 		return err;