diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index ef86ad243986..ae0e14b8880c 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -47,29 +47,31 @@ enum s390_regset {
 
 void update_per_regs(struct task_struct *task)
 {
-	static const struct per_regs per_single_step = {
-		.control = PER_EVENT_IFETCH,
-		.start = 0,
-		.end = PSW_ADDR_INSN,
-	};
 	struct pt_regs *regs = task_pt_regs(task);
 	struct thread_struct *thread = &task->thread;
-	const struct per_regs *new;
-	struct per_regs old;
+	struct per_regs old, new;
 
-	/* TIF_SINGLE_STEP overrides the user specified PER registers. */
-	new = test_tsk_thread_flag(task, TIF_SINGLE_STEP) ?
-		&per_single_step : &thread->per_user;
+	/* Copy user specified PER registers */
+	new.control = thread->per_user.control;
+	new.start = thread->per_user.start;
+	new.end = thread->per_user.end;
+
+	/* merge TIF_SINGLE_STEP into user specified PER registers. */
+	if (test_tsk_thread_flag(task, TIF_SINGLE_STEP)) {
+		new.control |= PER_EVENT_IFETCH;
+		new.start = 0;
+		new.end = PSW_ADDR_INSN;
+	}
 
 	/* Take care of the PER enablement bit in the PSW. */
-	if (!(new->control & PER_EVENT_MASK)) {
+	if (!(new.control & PER_EVENT_MASK)) {
 		regs->psw.mask &= ~PSW_MASK_PER;
 		return;
 	}
 	regs->psw.mask |= PSW_MASK_PER;
 	__ctl_store(old, 9, 11);
-	if (memcmp(new, &old, sizeof(struct per_regs)) != 0)
-		__ctl_load(*new, 9, 11);
+	if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
+		__ctl_load(new, 9, 11);
 }
 
 void user_enable_single_step(struct task_struct *task)