Index: ksrc/nucleus/shadow.c
===================================================================
--- ksrc/nucleus/shadow.c	(revision 719)
+++ ksrc/nucleus/shadow.c	(working copy)
@@ -1141,6 +1141,12 @@ static inline int do_hisyscall_event (un
     if (!__xn_reg_mux_p(regs))
 	goto linux_syscall;
 
+    if (unlikely(!cap_raised(p->cap_effective, CAP_SYS_NICE)))
+	{
+	__xn_error_return(regs,-EPERM);
+	return RTHAL_EVENT_STOP;
+	}
+
     muxid = __xn_mux_id(regs);
     muxop = __xn_mux_op(regs);