diff --git a/library/threading.c b/library/threading.c
index 06b4747..85db243 100644
--- a/library/threading.c
+++ b/library/threading.c
@@ -151,6 +151,7 @@
 #if defined(MBEDTLS_PSA_CRYPTO_C)
     mbedtls_mutex_init(&mbedtls_threading_key_slot_mutex);
     mbedtls_mutex_init(&mbedtls_threading_psa_globaldata_mutex);
+    mbedtls_mutex_init(&mbedtls_threading_psa_rngdata_mutex);
 #endif
 }
 
@@ -168,6 +169,7 @@
 #if defined(MBEDTLS_PSA_CRYPTO_C)
     mbedtls_mutex_free(&mbedtls_threading_key_slot_mutex);
     mbedtls_mutex_free(&mbedtls_threading_psa_globaldata_mutex);
+    mbedtls_mutex_free(&mbedtls_threading_psa_rngdata_mutex);
 #endif
 }
 #endif /* MBEDTLS_THREADING_ALT */
@@ -187,6 +189,7 @@
 #if defined(MBEDTLS_PSA_CRYPTO_C)
 mbedtls_threading_mutex_t mbedtls_threading_key_slot_mutex MUTEX_INIT;
 mbedtls_threading_mutex_t mbedtls_threading_psa_globaldata_mutex MUTEX_INIT;
+mbedtls_threading_mutex_t mbedtls_threading_psa_rngdata_mutex MUTEX_INIT;
 #endif
 
 #endif /* MBEDTLS_THREADING_C */