Index: pstk_compat.c
===================================================================
--- pstk_compat.c	(revision 15074)
+++ pstk_compat.c	(revision 15075)
@@ -121,6 +121,9 @@
 	pcb_pstk_tshape_t tshp;
 	int n;
 
+	assert(pad_dia > drill_dia);
+	assert(drill_dia > 0);
+
 	memset(&proto, 0, sizeof(proto));
 	memset(&tshp, 0, sizeof(tshp));
 	memset(&copper_master, 0, sizeof(copper_master));