diff --git a/common/libzkp/impl/src/utils.rs b/common/libzkp/impl/src/utils.rs
index 206dd1ef08..ecc3954e0f 100644
--- a/common/libzkp/impl/src/utils.rs
+++ b/common/libzkp/impl/src/utils.rs
@@ -16,9 +16,12 @@ pub(crate) static OUTPUT_DIR: Lazy<Option<String>> =
 pub extern "C" fn free_c_chars(ptr: *mut c_char) {
     log::info!("free_c_chars BEGIN");
     if !ptr.is_null() {
+        log::info!("free_c_chars NOT-NULL");
         unsafe {
             let _ = CString::from_raw(ptr);
         }
+    } else {
+        log::info!("free_c_chars NULL");
     }
     log::info!("free_c_chars END");
 }