diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index de801f22128a..07ab8e9733c5 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -387,7 +387,7 @@ NOKPROBE_SYMBOL(do_int3);
  * for scheduling or signal handling. The actual stack switch is done in
  * entry.S
  */
-asmlinkage __visible struct pt_regs *sync_regs(struct pt_regs *eregs)
+asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs)
 {
 	struct pt_regs *regs = eregs;
 	/* Did already sync */
@@ -413,7 +413,7 @@ struct bad_iret_stack {
 	struct pt_regs regs;
 };
 
-asmlinkage __visible
+asmlinkage __visible notrace
 struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
 {
 	/*
@@ -436,6 +436,7 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
 	BUG_ON(!user_mode_vm(&new_stack->regs));
 	return new_stack;
 }
+NOKPROBE_SYMBOL(fixup_bad_iret);
 #endif
 
 /*
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 09b9e8d3fcf7..c4ffe2bd0738 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -242,6 +242,7 @@ struct events_stats {
 	u32 nr_invalid_chains;
 	u32 nr_unknown_id;
 	u32 nr_unprocessable_samples;
+	u32 nr_unordered_events;
 };
 
 struct attr_event {
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 6ac62ae6b8fa..5f0e05a76c05 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -533,15 +533,11 @@ int perf_session_queue_event(struct perf_session *s, union perf_event *event,
 		return -ETIME;
 
 	if (timestamp < oe->last_flush) {
-		WARN_ONCE(1, "Timestamp below last timeslice flush\n");
-
-		pr_oe_time(timestamp,      "out of order event");
+		pr_oe_time(timestamp,      "out of order event\n");
 		pr_oe_time(oe->last_flush, "last flush, last_flush_type %d\n",
 			   oe->last_flush_type);
 
-		/* We could get out of order messages after forced flush. */
-		if (oe->last_flush_type != OE_FLUSH__HALF)
-			return -EINVAL;
+		s->stats.nr_unordered_events++;
 	}
 
 	new = ordered_events__new(oe, timestamp, event);
@@ -1118,6 +1114,9 @@ static void perf_session__warn_about_errors(const struct perf_session *session,
 			    "Do you have a KVM guest running and not using 'perf kvm'?\n",
 			    session->stats.nr_unprocessable_samples);
 	}
+
+	if (session->stats.nr_unordered_events != 0)
+		ui__warning("%u out of order events recorded.\n", session->stats.nr_unordered_events);
 }
 
 volatile int session_done;