diff --git a/benches/signature.rs b/benches/signature.rs
index c9370fa1c5..651d2766be 100644
--- a/benches/signature.rs
+++ b/benches/signature.rs
@@ -6,7 +6,7 @@ use criterion::{Bencher, Criterion};
 use solana::signature::GenKeys;
 
 fn bench_gen_keys(b: &mut Bencher) {
-    let rnd = GenKeys::new([0u8; 32]);
+    let mut rnd = GenKeys::new([0u8; 32]);
     b.iter(|| rnd.gen_n_keypairs(1000));
 }