diff --git a/ports/unix/input.c b/ports/unix/input.c
index 31926a5a8e..260e9eac8c 100644
--- a/ports/unix/input.c
+++ b/ports/unix/input.c
@@ -104,6 +104,9 @@ void prompt_write_history(void) {
     #if MICROPY_USE_READLINE == 1
     char *home = getenv("HOME");
     if (home != NULL) {
+        if (MP_STATE_THREAD(gc_lock_depth) != 0) {
+            return;
+        }
         vstr_t vstr;
         vstr_init(&vstr, 50);
         vstr_printf(&vstr, "%s/.micropython.history", home);