diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 8e9e05d3b419..60b84edc8a68 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -214,7 +214,6 @@ extern int os_protect_memory(void *addr, unsigned long len,
 extern int os_unmap_memory(void *addr, int len);
 extern int os_drop_memory(void *addr, int length);
 extern int can_drop_memory(void);
-extern void os_flush_stdout(void);
 extern int os_mincore(void *addr, unsigned long len);
 
 /* execvp.c */