diff --git a/src/calibre/gui2/progress_indicator/QProgressIndicator.sip b/src/calibre/gui2/progress_indicator/QProgressIndicator.sip
index 559f2b19d1..26f145b8fd 100644
--- a/src/calibre/gui2/progress_indicator/QProgressIndicator.sip
+++ b/src/calibre/gui2/progress_indicator/QProgressIndicator.sip
@@ -57,4 +57,4 @@ protected:
 
 int load_style(QHash<int,QString> icon_map, int transient_scroller);
 void set_no_activate_on_click(QWidget *widget);
-void draw_snake_spinner(QPainter &painter, QRect rect, int angle, const QColor & light, const QColor & dark);
+void draw_snake_spinner(QPainter &painter, QRect rect, int angle, const QColor & light, const QColor & dark) /ReleaseGIL/;