Merge release-20190806.1-221-gdd69b49 (automated)

1 files changed, 20 insertions, 7 deletions

diff --git a/pkg/sentry/kernel/time/time.go b/pkg/sentry/kernel/time/time.go
index aa6c75d25..107394183 100644
--- a/pkg/sentry/kernel/time/time.go
+++ b/pkg/sentry/kernel/time/time.go
@@ -280,13 +280,16 @@ func (ClockEventsQueue) Readiness(mask waiter.EventMask) waiter.EventMask {
 // A TimerListener receives expirations from a Timer.
 type TimerListener interface {
 	// Notify is called when its associated Timer expires. exp is the number of
-	// expirations.
+	// expirations. setting is the next timer Setting.
 	//
 	// Notify is called with the associated Timer's mutex locked, so Notify
 	// must not take any locks that precede Timer.mu in lock order.
 	//
+	// If Notify returns true, the timer will use the returned setting
+	// rather than the passed one.
+	//
 	// Preconditions: exp > 0.
-	Notify(exp uint64)
+	Notify(exp uint64, setting Setting) (newSetting Setting, update bool)
 
 	// Destroy is called when the timer is destroyed.
 	Destroy()
@@ -533,7 +536,9 @@ func (t *Timer) Tick() {
 	s, exp := t.setting.At(now)
 	t.setting = s
 	if exp > 0 {
-		t.listener.Notify(exp)
+		if newS, ok := t.listener.Notify(exp, t.setting); ok {
+			t.setting = newS
+		}
 	}
 	t.resetKickerLocked(now)
 }
@@ -588,7 +593,9 @@ func (t *Timer) Get() (Time, Setting) {
 	s, exp := t.setting.At(now)
 	t.setting = s
 	if exp > 0 {
-		t.listener.Notify(exp)
+		if newS, ok := t.listener.Notify(exp, t.setting); ok {
+			t.setting = newS
+		}
 	}
 	t.resetKickerLocked(now)
 	return now, s
@@ -620,7 +627,9 @@ func (t *Timer) SwapAnd(s Setting, f func()) (Time, Setting) {
 	}
 	oldS, oldExp := t.setting.At(now)
 	if oldExp > 0 {
-		t.listener.Notify(oldExp)
+		t.listener.Notify(oldExp, oldS)
+		// N.B. The returned Setting doesn't matter because we're about
+		// to overwrite.
 	}
 	if f != nil {
 		f()
@@ -628,7 +637,9 @@ func (t *Timer) SwapAnd(s Setting, f func()) (Time, Setting) {
 	newS, newExp := s.At(now)
 	t.setting = newS
 	if newExp > 0 {
-		t.listener.Notify(newExp)
+		if newS, ok := t.listener.Notify(newExp, t.setting); ok {
+			t.setting = newS
+		}
 	}
 	t.resetKickerLocked(now)
 	return now, oldS
@@ -683,11 +694,13 @@ func NewChannelNotifier() (TimerListener, <-chan struct{}) {
 }
 
 // Notify implements ktime.TimerListener.Notify.
-func (c *ChannelNotifier) Notify(uint64) {
+func (c *ChannelNotifier) Notify(uint64, Setting) (Setting, bool) {
 	select {
 	case c.tchan <- struct{}{}:
 	default:
 	}
+
+	return Setting{}, false
 }
 
 // Destroy implements ktime.TimerListener.Destroy and will close the channel.