diff --git a/sys/kern/kern_varsym.c b/sys/kern/kern_varsym.c
--- a/sys/kern/kern_varsym.c
+++ b/sys/kern/kern_varsym.c
@@ -261,7 +261,10 @@
 			vss = &td->td_ucred->cr_uidinfo->ui_varsymset;
 		break;
 	case VARSYM_SYS:
-		vss = &varsymset_sys;
+		if (lp != NULL && td->td_ucred->cr_prison != NULL)
+			vss = &td->td_ucred->cr_prison->pr_varsymset;
+		else
+			vss = &varsymset_sys;
 		break;
 	case VARSYM_PRISON:
 		if (lp && td->td_ucred->cr_prison)