diff -up ./arch/x86/include/asm/sync_core.h.pti ./arch/x86/include/asm/sync_core.h

--- ./arch/x86/include/asm/sync_core.h.pti	2018-10-05 05:18:19.000000000 +0900

+++ ./arch/x86/include/asm/sync_core.h	2018-10-31 18:57:31.000000000 +0900

@@ -14,9 +14,11 @@

  */

 static inline void sync_core_before_usermode(void)

 {

+#ifdef CONFIG_PAGE_TABLE_ISOLATION

 	/* With PTI, we unconditionally serialize before running user code. */

 	if (kaiser_active())

 		return;

+#endif

 	/*

 	 * Return from interrupt and NMI is done through iret, which is core

 	 * serializing.