diff --git a/kernel/exit.c b/kernel/exit.c
index b0eea830303c..10e088237fed 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -59,8 +59,6 @@
 #include <asm/pgtable.h>
 #include <asm/mmu_context.h>
 
-static void exit_mm(struct task_struct *tsk);
-
 static void __unhash_process(struct task_struct *p, bool group_dead)
 {
 	nr_threads--;