diff --git a/source/tools/detect/sched/schedmoni/irqoff.c b/source/tools/detect/sched/schedmoni/irqoff.c
index e2cdbb4dd5fce7b883f79f83646c78bcd58c82b7..9c04448dfc6a646f65aeceb08781adc5c76014f9 100644
--- a/source/tools/detect/sched/schedmoni/irqoff.c
+++ b/source/tools/detect/sched/schedmoni/irqoff.c
@@ -81,7 +81,7 @@ int attach_prog_to_perf(struct schedmoni_bpf *obj, struct bpf_link **sw_mlinks,
 	return !ret;
 }
 
-char stack[512];
+static char stack[512];
 void irqoff_handle_event(void *ctx, int cpu, void *data, __u32 data_sz)
 {
 	struct event ev, *e;
diff --git a/source/tools/detect/sched/schedmoni/nosched.c b/source/tools/detect/sched/schedmoni/nosched.c
index d5e29a844b24655ad4b01a6494afc3e7e212557e..15f0446b742f2f7bf2b2307d79a2f162cc1df0c8 100644
--- a/source/tools/detect/sched/schedmoni/nosched.c
+++ b/source/tools/detect/sched/schedmoni/nosched.c
@@ -19,7 +19,7 @@ extern volatile sig_atomic_t exiting;
 extern struct ksym *ksyms;
 static int stack_fd;
 
-char stack[512];
+static char stack[512];
 void handle_event_nosch(void *ctx, int cpu, void *data, __u32 data_sz)
 {
 	const struct event *e = data;