diff --git a/tests/fuzz/fuzz_client.c b/tests/fuzz/fuzz_client.c
index 7860177a17..2f439f5996 100644
--- a/tests/fuzz/fuzz_client.c
+++ b/tests/fuzz/fuzz_client.c
@@ -78,6 +78,7 @@ static int dummy_random( void *p_rng, unsigned char *output, size_t output_len )
 static int dummy_entropy( void *data, unsigned char *output, size_t len )
 {
     size_t i;
+    (void) data;
 
     //use mbedtls_entropy_func to find bugs in it
     //test performance impact of entropy
diff --git a/tests/fuzz/fuzz_dtlsclient.c b/tests/fuzz/fuzz_dtlsclient.c
index c88b33b739..424af81117 100644
--- a/tests/fuzz/fuzz_dtlsclient.c
+++ b/tests/fuzz/fuzz_dtlsclient.c
@@ -79,6 +79,7 @@ static int dummy_random( void *p_rng, unsigned char *output, size_t output_len )
 static int dummy_entropy( void *data, unsigned char *output, size_t len )
 {
     size_t i;
+    (void) data;
 
     //use mbedtls_entropy_func to find bugs in it
     //test performance impact of entropy
diff --git a/tests/fuzz/fuzz_dtlsserver.c b/tests/fuzz/fuzz_dtlsserver.c
index 6e59a85a7c..6f31bfbe25 100644
--- a/tests/fuzz/fuzz_dtlsserver.c
+++ b/tests/fuzz/fuzz_dtlsserver.c
@@ -80,6 +80,7 @@ static int dummy_random( void *p_rng, unsigned char *output, size_t output_len )
 static int dummy_entropy( void *data, unsigned char *output, size_t len )
 {
     size_t i;
+    (void) data;
 
     //use mbedtls_entropy_func to find bugs in it
     //test performance impact of entropy
diff --git a/tests/fuzz/fuzz_server.c b/tests/fuzz/fuzz_server.c
index 770a38633c..f8882dd85b 100644
--- a/tests/fuzz/fuzz_server.c
+++ b/tests/fuzz/fuzz_server.c
@@ -79,6 +79,7 @@ static int dummy_random( void *p_rng, unsigned char *output, size_t output_len )
 static int dummy_entropy( void *data, unsigned char *output, size_t len )
 {
     size_t i;
+    (void) data;
 
     //use mbedtls_entropy_func to find bugs in it
     //test performance impact of entropy