diff --git a/library/ecp.c b/library/ecp.c
index 229b28e..beab9c4 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -244,6 +244,7 @@
  */
 void mbedtls_ecp_restart_init( mbedtls_ecp_restart_ctx *ctx )
 {
+    ECP_VALIDATE( ctx != NULL );
     ctx->ops_done = 0;
     ctx->depth = 0;
     ctx->rsm = NULL;