Merge release-20201030.0-53-g0fb5353e4 (automated)

11 files changed, 135 insertions, 81 deletions

diff --git a/pkg/sentry/kernel/fd_table_refs.go b/pkg/sentry/kernel/fd_table_refs.go
index 992606f36..f540ba371 100644
--- a/pkg/sentry/kernel/fd_table_refs.go
+++ b/pkg/sentry/kernel/fd_table_refs.go
@@ -20,9 +20,6 @@ var FDTableobj *FDTable
 // 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 FDTableRefs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type FDTableRefs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *FDTableRefs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *FDTableRefs) RefType() string {
 	return fmt.Sprintf("%T", FDTableobj)[1:]
@@ -58,8 +62,7 @@ func (r *FDTableRefs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *FDTableRefs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *FDTableRefs) ReadRefs() int64 {
 //go:nosplit
 func (r *FDTableRefs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if FDTableenableLogging {
+		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 *FDTableRefs) IncRef() {
 //go:nosplit
 func (r *FDTableRefs) 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 FDTableenableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *FDTableRefs) TryIncRef() bool {
 //go:nosplit
 func (r *FDTableRefs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if FDTableenableLogging {
+		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/kernel/fd_table_unsafe.go b/pkg/sentry/kernel/fd_table_unsafe.go
index 3476551f3..470d8bf83 100644
--- a/pkg/sentry/kernel/fd_table_unsafe.go
+++ b/pkg/sentry/kernel/fd_table_unsafe.go
@@ -43,7 +43,7 @@ func (f *FDTable) initNoLeakCheck() {
 // init initializes the table with leak checking.
 func (f *FDTable) init() {
 	f.initNoLeakCheck()
-	f.EnableLeakCheck()
+	f.InitRefs()
 }
 
 // get gets a file entry.
diff --git a/pkg/sentry/kernel/fs_context.go b/pkg/sentry/kernel/fs_context.go
index 41fb2a784..dfde4deee 100644
--- a/pkg/sentry/kernel/fs_context.go
+++ b/pkg/sentry/kernel/fs_context.go
@@ -63,7 +63,7 @@ func newFSContext(root, cwd *fs.Dirent, umask uint) *FSContext {
 		cwd:   cwd,
 		umask: umask,
 	}
-	f.EnableLeakCheck()
+	f.InitRefs()
 	return &f
 }
 
@@ -76,7 +76,7 @@ func NewFSContextVFS2(root, cwd vfs.VirtualDentry, umask uint) *FSContext {
 		cwdVFS2:  cwd,
 		umask:    umask,
 	}
-	f.EnableLeakCheck()
+	f.InitRefs()
 	return &f
 }
 
@@ -137,7 +137,7 @@ func (f *FSContext) Fork() *FSContext {
 		rootVFS2: f.rootVFS2,
 		umask:    f.umask,
 	}
-	ctx.EnableLeakCheck()
+	ctx.InitRefs()
 	return ctx
 }
 
diff --git a/pkg/sentry/kernel/fs_context_refs.go b/pkg/sentry/kernel/fs_context_refs.go
index ff812ab16..6510157c7 100644
--- a/pkg/sentry/kernel/fs_context_refs.go
+++ b/pkg/sentry/kernel/fs_context_refs.go
@@ -20,9 +20,6 @@ var FSContextobj *FSContext
 // 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 FSContextRefs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type FSContextRefs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *FSContextRefs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *FSContextRefs) RefType() string {
 	return fmt.Sprintf("%T", FSContextobj)[1:]
@@ -58,8 +62,7 @@ func (r *FSContextRefs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *FSContextRefs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *FSContextRefs) ReadRefs() int64 {
 //go:nosplit
 func (r *FSContextRefs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if FSContextenableLogging {
+		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 *FSContextRefs) IncRef() {
 //go:nosplit
 func (r *FSContextRefs) 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 FSContextenableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *FSContextRefs) TryIncRef() bool {
 //go:nosplit
 func (r *FSContextRefs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if FSContextenableLogging {
+		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/kernel/ipc_namespace.go b/pkg/sentry/kernel/ipc_namespace.go
index b87e40dd1..9545bb5ef 100644
--- a/pkg/sentry/kernel/ipc_namespace.go
+++ b/pkg/sentry/kernel/ipc_namespace.go
@@ -41,7 +41,7 @@ func NewIPCNamespace(userNS *auth.UserNamespace) *IPCNamespace {
 		semaphores: semaphore.NewRegistry(userNS),
 		shms:       shm.NewRegistry(userNS),
 	}
-	ns.EnableLeakCheck()
+	ns.InitRefs()
 	return ns
 }
 
diff --git a/pkg/sentry/kernel/ipc_namespace_refs.go b/pkg/sentry/kernel/ipc_namespace_refs.go
index 5b37e617a..c0acf2f50 100644
--- a/pkg/sentry/kernel/ipc_namespace_refs.go
+++ b/pkg/sentry/kernel/ipc_namespace_refs.go
@@ -20,9 +20,6 @@ var IPCNamespaceobj *IPCNamespace
 // 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 IPCNamespaceRefs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type IPCNamespaceRefs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *IPCNamespaceRefs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *IPCNamespaceRefs) RefType() string {
 	return fmt.Sprintf("%T", IPCNamespaceobj)[1:]
@@ -58,8 +62,7 @@ func (r *IPCNamespaceRefs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *IPCNamespaceRefs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *IPCNamespaceRefs) ReadRefs() int64 {
 //go:nosplit
 func (r *IPCNamespaceRefs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if IPCNamespaceenableLogging {
+		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 *IPCNamespaceRefs) IncRef() {
 //go:nosplit
 func (r *IPCNamespaceRefs) 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 IPCNamespaceenableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *IPCNamespaceRefs) TryIncRef() bool {
 //go:nosplit
 func (r *IPCNamespaceRefs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if IPCNamespaceenableLogging {
+		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/kernel/process_group_refs.go b/pkg/sentry/kernel/process_group_refs.go
index 29bd0b80f..a9cc69b35 100644
--- a/pkg/sentry/kernel/process_group_refs.go
+++ b/pkg/sentry/kernel/process_group_refs.go
@@ -20,9 +20,6 @@ var ProcessGroupobj *ProcessGroup
 // 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 ProcessGroupRefs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type ProcessGroupRefs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *ProcessGroupRefs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *ProcessGroupRefs) RefType() string {
 	return fmt.Sprintf("%T", ProcessGroupobj)[1:]
@@ -58,8 +62,7 @@ func (r *ProcessGroupRefs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *ProcessGroupRefs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *ProcessGroupRefs) ReadRefs() int64 {
 //go:nosplit
 func (r *ProcessGroupRefs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if ProcessGroupenableLogging {
+		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 *ProcessGroupRefs) IncRef() {
 //go:nosplit
 func (r *ProcessGroupRefs) 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 ProcessGroupenableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *ProcessGroupRefs) TryIncRef() bool {
 //go:nosplit
 func (r *ProcessGroupRefs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if ProcessGroupenableLogging {
+		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/kernel/session_refs.go b/pkg/sentry/kernel/session_refs.go
index 430cb131c..0856ff261 100644
--- a/pkg/sentry/kernel/session_refs.go
+++ b/pkg/sentry/kernel/session_refs.go
@@ -20,9 +20,6 @@ var Sessionobj *Session
 // 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 SessionRefs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type SessionRefs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *SessionRefs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *SessionRefs) RefType() string {
 	return fmt.Sprintf("%T", Sessionobj)[1:]
@@ -58,8 +62,7 @@ func (r *SessionRefs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *SessionRefs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *SessionRefs) ReadRefs() int64 {
 //go:nosplit
 func (r *SessionRefs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if SessionenableLogging {
+		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 *SessionRefs) IncRef() {
 //go:nosplit
 func (r *SessionRefs) 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 SessionenableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *SessionRefs) TryIncRef() bool {
 //go:nosplit
 func (r *SessionRefs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if SessionenableLogging {
+		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/kernel/sessions.go b/pkg/sentry/kernel/sessions.go
index 5bddb0a36..0cd9e2533 100644
--- a/pkg/sentry/kernel/sessions.go
+++ b/pkg/sentry/kernel/sessions.go
@@ -295,7 +295,7 @@ func (tg *ThreadGroup) createSession() error {
 		id:     SessionID(id),
 		leader: tg,
 	}
-	s.EnableLeakCheck()
+	s.InitRefs()
 
 	// Create a new ProcessGroup, belonging to that Session.
 	// This also has a single reference (assigned below).
@@ -309,7 +309,7 @@ func (tg *ThreadGroup) createSession() error {
 		session:    s,
 		ancestors:  0,
 	}
-	pg.refs.EnableLeakCheck()
+	pg.refs.InitRefs()
 
 	// Tie them and return the result.
 	s.processGroups.PushBack(pg)
@@ -395,7 +395,7 @@ func (tg *ThreadGroup) CreateProcessGroup() error {
 		originator: tg,
 		session:    tg.processGroup.session,
 	}
-	pg.refs.EnableLeakCheck()
+	pg.refs.InitRefs()
 
 	if tg.leader.parent != nil && tg.leader.parent.tg.processGroup.session == pg.session {
 		pg.ancestors++
diff --git a/pkg/sentry/kernel/shm/shm.go b/pkg/sentry/kernel/shm/shm.go
index ebbebf46b..92d60ba78 100644
--- a/pkg/sentry/kernel/shm/shm.go
+++ b/pkg/sentry/kernel/shm/shm.go
@@ -251,7 +251,7 @@ func (r *Registry) newShm(ctx context.Context, pid int32, key Key, creator fs.Fi
 		creatorPID:    pid,
 		changeTime:    ktime.NowFromContext(ctx),
 	}
-	shm.EnableLeakCheck()
+	shm.InitRefs()
 
 	// Find the next available ID.
 	for id := r.lastIDUsed + 1; id != r.lastIDUsed; id++ {
diff --git a/pkg/sentry/kernel/shm/shm_refs.go b/pkg/sentry/kernel/shm/shm_refs.go
index 5f148594c..82ca1ed06 100644
--- a/pkg/sentry/kernel/shm/shm_refs.go
+++ b/pkg/sentry/kernel/shm/shm_refs.go
@@ -20,9 +20,6 @@ var Shmobj *Shm
 // 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 ShmRefs struct {
 	// refCount is composed of two fields:
@@ -35,6 +32,13 @@ type ShmRefs struct {
 	refCount int64
 }
 
+// InitRefs initializes r with one reference and, if enabled, activates leak
+// checking.
+func (r *ShmRefs) InitRefs() {
+	atomic.StoreInt64(&r.refCount, 1)
+	refsvfs2.Register(r)
+}
+
 // RefType implements refsvfs2.CheckedObject.RefType.
 func (r *ShmRefs) RefType() string {
 	return fmt.Sprintf("%T", Shmobj)[1:]
@@ -58,8 +62,7 @@ func (r *ShmRefs) EnableLeakCheck() {
 // ReadRefs returns the current number of references. The returned count is
 // inherently racy and is unsafe to use without external synchronization.
 func (r *ShmRefs) ReadRefs() int64 {
-
-	return atomic.LoadInt64(&r.refCount) + 1
+	return atomic.LoadInt64(&r.refCount)
 }
 
 // IncRef implements refs.RefCounter.IncRef.
@@ -67,8 +70,10 @@ func (r *ShmRefs) ReadRefs() int64 {
 //go:nosplit
 func (r *ShmRefs) IncRef() {
 	v := atomic.AddInt64(&r.refCount, 1)
-	refsvfs2.LogIncRef(r, v+1)
-	if v <= 0 {
+	if ShmenableLogging {
+		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 *ShmRefs) IncRef() {
 //go:nosplit
 func (r *ShmRefs) 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 ShmenableLogging {
+		refsvfs2.LogTryIncRef(r, v)
+	}
 	return true
 }
 
@@ -107,12 +114,14 @@ func (r *ShmRefs) TryIncRef() bool {
 //go:nosplit
 func (r *ShmRefs) DecRef(destroy func()) {
 	v := atomic.AddInt64(&r.refCount, -1)
-	refsvfs2.LogDecRef(r, v+1)
+	if ShmenableLogging {
+		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 {