diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3c41149..a5fa1fd 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -708,6 +708,7 @@
 	.write		= oom_adjust_write,
 };
 
+#ifdef CONFIG_MMU
 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
@@ -741,6 +742,7 @@
 static struct file_operations proc_clear_refs_operations = {
 	.write		= clear_refs_write,
 };
+#endif
 
 #ifdef CONFIG_AUDITSYSCALL
 #define TMPBUFLEN 21