Merge release-20201030.0-53-g0fb5353e4 (automated)

7 files changed, 70 insertions, 43 deletions

diff --git a/pkg/sentry/socket/unix/socket_refs.go b/pkg/sentry/socket/unix/socket_refs.go
index aec464529..e69a17ca8 100644
--- a/pkg/sentry/socket/unix/socket_refs.go
+++ b/pkg/sentry/socket/unix/socket_refs.go
@@ -20,9 +20,6 @@ var socketOperationsobj *SocketOperations
 // Refs implements refs.RefCounter. It keeps a reference count using atomic
 // operations and calls the destructor when the count reaches zero.
 //
-// Note that the number of references is actually refCount + 1 so that a default
-// zero-value Refs object contains one reference.
-//
 // +stateify savable
 type socketOperationsRefs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type socketOperationsRefs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *socketOperationsRefs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *socketOperationsRefs) RefType() string {
 	return fmt.Sprintf("%T", socketOperationsobj)[1:]
@@ -58,8 +62,7 @@ func (r *socketOperationsRefs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *socketOperationsRefs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *socketOperationsRefs) ReadRefs() int64 {
 //go:nosplit
 func (r *socketOperationsRefs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if socketOperationsenableLogging {
+		refsvfs2.LogIncRef(r, v)
+	}
+	if v <= 1 {
 		panic(fmt.Sprintf("Incrementing non-positive count %p on %s", r, r.RefType()))
 	}
 }
@@ -82,14 +87,16 @@ func (r *socketOperationsRefs) IncRef() {
 //go:nosplit
 func (r *socketOperationsRefs) TryIncRef() bool {
 	const speculativeRef = 1 << 32
-	if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) < 0 {
+	if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) == 0 {
 
 		atomic.AddInt64(&r.refCount, -speculativeRef)
 		return false
 	}
 
 	v := atomic.AddInt64(&r.refCount, -speculativeRef+1)
-	refsvfs2.LogTryIncRef(r, v+1)
+	if socketOperationsenableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *socketOperationsRefs) TryIncRef() bool {
 //go:nosplit
 func (r *socketOperationsRefs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if socketOperationsenableLogging {
+		refsvfs2.LogDecRef(r, v+1)
+	}
 	switch {
-	case v < -1:
+	case v < 0:
 		panic(fmt.Sprintf("Decrementing non-positive ref count %p, owned by %s", r, r.RefType()))
 
-	case v == -1:
+	case v == 0:
 		refsvfs2.Unregister(r)
 
 		if destroy != nil {
diff --git a/pkg/sentry/socket/unix/socket_vfs2_refs.go b/pkg/sentry/socket/unix/socket_vfs2_refs.go
index 8794375b3..d9bdba0b3 100644
--- a/pkg/sentry/socket/unix/socket_vfs2_refs.go
+++ b/pkg/sentry/socket/unix/socket_vfs2_refs.go
@@ -20,9 +20,6 @@ var socketVFS2obj *SocketVFS2
 // Refs implements refs.RefCounter. It keeps a reference count using atomic
 // operations and calls the destructor when the count reaches zero.
 //
-// Note that the number of references is actually refCount + 1 so that a default
-// zero-value Refs object contains one reference.
-//
 // +stateify savable
 type socketVFS2Refs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type socketVFS2Refs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *socketVFS2Refs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *socketVFS2Refs) RefType() string {
 	return fmt.Sprintf("%T", socketVFS2obj)[1:]
@@ -58,8 +62,7 @@ func (r *socketVFS2Refs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *socketVFS2Refs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *socketVFS2Refs) ReadRefs() int64 {
 //go:nosplit
 func (r *socketVFS2Refs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if socketVFS2enableLogging {
+		refsvfs2.LogIncRef(r, v)
+	}
+	if v <= 1 {
 		panic(fmt.Sprintf("Incrementing non-positive count %p on %s", r, r.RefType()))
 	}
 }
@@ -82,14 +87,16 @@ func (r *socketVFS2Refs) IncRef() {
 //go:nosplit
 func (r *socketVFS2Refs) TryIncRef() bool {
 	const speculativeRef = 1 << 32
-	if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) < 0 {
+	if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) == 0 {
 
 		atomic.AddInt64(&r.refCount, -speculativeRef)
 		return false
 	}
 
 	v := atomic.AddInt64(&r.refCount, -speculativeRef+1)
-	refsvfs2.LogTryIncRef(r, v+1)
+	if socketVFS2enableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *socketVFS2Refs) TryIncRef() bool {
 //go:nosplit
 func (r *socketVFS2Refs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if socketVFS2enableLogging {
+		refsvfs2.LogDecRef(r, v+1)
+	}
 	switch {
-	case v < -1:
+	case v < 0:
 		panic(fmt.Sprintf("Decrementing non-positive ref count %p, owned by %s", r, r.RefType()))
 
-	case v == -1:
+	case v == 0:
 		refsvfs2.Unregister(r)
 
 		if destroy != nil {
diff --git a/pkg/sentry/socket/unix/transport/connectioned.go b/pkg/sentry/socket/unix/transport/connectioned.go
index aa4f3c04d..6d9e502bd 100644
--- a/pkg/sentry/socket/unix/transport/connectioned.go
+++ b/pkg/sentry/socket/unix/transport/connectioned.go
@@ -142,9 +142,9 @@ func NewPair(ctx context.Context, stype linux.SockType, uid UniqueIDProvider) (E
 	}
 
 	q1 := &queue{ReaderQueue: a.Queue, WriterQueue: b.Queue, limit: initialLimit}
-	q1.EnableLeakCheck()
+	q1.InitRefs()
 	q2 := &queue{ReaderQueue: b.Queue, WriterQueue: a.Queue, limit: initialLimit}
-	q2.EnableLeakCheck()
+	q2.InitRefs()
 
 	if stype == linux.SOCK_STREAM {
 		a.receiver = &streamQueueReceiver{queueReceiver: queueReceiver{q1}}
@@ -300,14 +300,14 @@ func (e *connectionedEndpoint) BidirectionalConnect(ctx context.Context, ce Conn
 	}
 
 	readQueue := &queue{ReaderQueue: ce.WaiterQueue(), WriterQueue: ne.Queue, limit: initialLimit}
-	readQueue.EnableLeakCheck()
+	readQueue.InitRefs()
 	ne.connected = &connectedEndpoint{
 		endpoint:   ce,
 		writeQueue: readQueue,
 	}
 
 	writeQueue := &queue{ReaderQueue: ne.Queue, WriterQueue: ce.WaiterQueue(), limit: initialLimit}
-	writeQueue.EnableLeakCheck()
+	writeQueue.InitRefs()
 	if e.stype == linux.SOCK_STREAM {
 		ne.receiver = &streamQueueReceiver{queueReceiver: queueReceiver{readQueue: writeQueue}}
 	} else {
diff --git a/pkg/sentry/socket/unix/transport/connectionless.go b/pkg/sentry/socket/unix/transport/connectionless.go
index f8aacca13..1406971bc 100644
--- a/pkg/sentry/socket/unix/transport/connectionless.go
+++ b/pkg/sentry/socket/unix/transport/connectionless.go
@@ -42,7 +42,7 @@ var (
 func NewConnectionless(ctx context.Context) Endpoint {
 	ep := &connectionlessEndpoint{baseEndpoint{Queue: &waiter.Queue{}}}
 	q := queue{ReaderQueue: ep.Queue, WriterQueue: &waiter.Queue{}, limit: initialLimit}
-	q.EnableLeakCheck()
+	q.InitRefs()
 	ep.receiver = &queueReceiver{readQueue: &q}
 	return ep
 }
diff --git a/pkg/sentry/socket/unix/transport/queue_refs.go b/pkg/sentry/socket/unix/transport/queue_refs.go
index ec67d4b14..679cb40e4 100644
--- a/pkg/sentry/socket/unix/transport/queue_refs.go
+++ b/pkg/sentry/socket/unix/transport/queue_refs.go
@@ -20,9 +20,6 @@ var queueobj *queue
 // Refs implements refs.RefCounter. It keeps a reference count using atomic
 // operations and calls the destructor when the count reaches zero.
 //
-// Note that the number of references is actually refCount + 1 so that a default
-// zero-value Refs object contains one reference.
-//
 // +stateify savable
 type queueRefs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type queueRefs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *queueRefs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *queueRefs) RefType() string {
 	return fmt.Sprintf("%T", queueobj)[1:]
@@ -58,8 +62,7 @@ func (r *queueRefs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *queueRefs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *queueRefs) ReadRefs() int64 {
 //go:nosplit
 func (r *queueRefs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if queueenableLogging {
+		refsvfs2.LogIncRef(r, v)
+	}
+	if v <= 1 {
 		panic(fmt.Sprintf("Incrementing non-positive count %p on %s", r, r.RefType()))
 	}
 }
@@ -82,14 +87,16 @@ func (r *queueRefs) IncRef() {
 //go:nosplit
 func (r *queueRefs) TryIncRef() bool {
 	const speculativeRef = 1 << 32
-	if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) < 0 {
+	if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) == 0 {
 
 		atomic.AddInt64(&r.refCount, -speculativeRef)
 		return false
 	}
 
 	v := atomic.AddInt64(&r.refCount, -speculativeRef+1)
-	refsvfs2.LogTryIncRef(r, v+1)
+	if queueenableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *queueRefs) TryIncRef() bool {
 //go:nosplit
 func (r *queueRefs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if queueenableLogging {
+		refsvfs2.LogDecRef(r, v+1)
+	}
 	switch {
-	case v < -1:
+	case v < 0:
 		panic(fmt.Sprintf("Decrementing non-positive ref count %p, owned by %s", r, r.RefType()))
 
-	case v == -1:
+	case v == 0:
 		refsvfs2.Unregister(r)
 
 		if destroy != nil {
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go
index adad485a9..b32bb7ba8 100644
--- a/pkg/sentry/socket/unix/unix.go
+++ b/pkg/sentry/socket/unix/unix.go
@@ -80,7 +80,7 @@ func NewWithDirent(ctx context.Context, d *fs.Dirent, ep transport.Endpoint, sty
 			stype: stype,
 		},
 	}
-	s.EnableLeakCheck()
+	s.InitRefs()
 	return fs.NewFile(ctx, d, flags, &s)
 }
 
diff --git a/pkg/sentry/socket/unix/unix_vfs2.go b/pkg/sentry/socket/unix/unix_vfs2.go
index 7a78444dc..eaf0b0d26 100644
--- a/pkg/sentry/socket/unix/unix_vfs2.go
+++ b/pkg/sentry/socket/unix/unix_vfs2.go
@@ -80,7 +80,7 @@ func NewFileDescription(ep transport.Endpoint, stype linux.SockType, flags uint3
 			stype: stype,
 		},
 	}
-	sock.EnableLeakCheck()
+	sock.InitRefs()
 	sock.LockFD.Init(locks)
 	vfsfd := &sock.vfsfd
 	if err := vfsfd.Init(sock, flags, mnt, d, &vfs.FileDescriptionOptions{