Index: kernel/arch/amd64/src/syscall.c
===================================================================
--- kernel/arch/amd64/src/syscall.c	(revision c15b37446cc540323e335d60ebc0166256615461)
+++ kernel/arch/amd64/src/syscall.c	(revision d0294342dd3ac03e0c663f4db0665ad183ac8bea)
@@ -66,6 +66,7 @@
 	 * - clear DF so that the string instructions operate in
 	 *   the right direction
+	 * - clear NT to prevent a #GP should the flag proliferate to an IRET
 	 */
-	write_msr(AMD_MSR_SFMASK, RFLAGS_IF | RFLAGS_DF);
+	write_msr(AMD_MSR_SFMASK, RFLAGS_IF | RFLAGS_DF | RFLAGS_NT);
 }