diff --git a/common/utils.c b/common/utils.c
index f51094f41..01047ea57 100644
--- a/common/utils.c
+++ b/common/utils.c
@@ -1,4 +1,5 @@
 #include "config.h"
+#include <assert.h>
 #include <bitcoin/chainparams.h>
 #include <ccan/list/list.h>
 #include <ccan/mem/mem.h>
@@ -99,6 +100,8 @@ void setup_locale(void)
 /* Initial creation of tmpctx. */
 void setup_tmpctx(void)
 {
+	/* Don't call me twice! */
+	assert(!tmpctx);
 	tmpctx = tal_arr_label(NULL, char, 0, "tmpctx");
 }
 
diff --git a/devtools/route.c b/devtools/route.c
index d13e3cf9d..90a7de058 100644
--- a/devtools/route.c
+++ b/devtools/route.c
@@ -28,9 +28,6 @@ static struct route_hop *least_cost(struct gossmap *map,
 	struct route_hop *path;
 	struct timemono tstart, tstop;
 
-	setup_locale();
-	setup_tmpctx();
-
 	tstart = time_mono();
 	dij = dijkstra(tmpctx, map, dst,
 		       sent, riskfactor, route_can_carry,
diff --git a/openingd/dualopend.c b/openingd/dualopend.c
index 9ac43d87a..159a418aa 100644
--- a/openingd/dualopend.c
+++ b/openingd/dualopend.c
@@ -4334,7 +4334,7 @@ static void fetch_per_commitment_point(u32 point_count,
 
 int main(int argc, char *argv[])
 {
-	common_setup(argv[0]);
+	setup_locale();
 
 	struct pollfd pollfd[2];
 	struct state *state = tal(NULL, struct state);