diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index deafb65..a29693f 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -14,6 +14,7 @@
  */
 #include <linux/sched.h>
 #include <linux/err.h>
+#include <linux/slab.h>
 #include <linux/smp.h>
 
 #include <asm/paravirt.h>