Initialize references with a value of 1.

This lets us avoid treating a value of 0 as one reference. All references
using the refsvfs2 template must call InitRefs() before the reference is
incremented/decremented, or else a panic will occur. Therefore, it should be
pretty easy to identify missing InitRef calls during testing.

Updates #1486.

PiperOrigin-RevId: 341411151

17 files changed, 63 insertions, 36 deletions

diff --git a/pkg/sentry/fsimpl/devpts/devpts.go b/pkg/sentry/fsimpl/devpts/devpts.go
index 346cca558..d8c237753 100644
--- a/pkg/sentry/fsimpl/devpts/devpts.go
+++ b/pkg/sentry/fsimpl/devpts/devpts.go
@@ -110,7 +110,7 @@ func (fstype *FilesystemType) newFilesystem(ctx context.Context, vfsObj *vfs.Vir
 	}
 	root.InodeAttrs.Init(ctx, creds, linux.UNNAMED_MAJOR, devMinor, 1, linux.ModeDirectory|0555)
 	root.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
-	root.EnableLeakCheck()
+	root.InitRefs()
 
 	var rootD kernfs.Dentry
 	rootD.InitRoot(&fs.Filesystem, root)
diff --git a/pkg/sentry/fsimpl/fuse/fusefs.go b/pkg/sentry/fsimpl/fuse/fusefs.go
index 6de416da0..cd0eb56e5 100644
--- a/pkg/sentry/fsimpl/fuse/fusefs.go
+++ b/pkg/sentry/fsimpl/fuse/fusefs.go
@@ -219,16 +219,12 @@ func newFUSEFilesystem(ctx context.Context, devMinor uint32, opts *filesystemOpt
 	}
 
 	fuseFD := device.Impl().(*DeviceFD)
-
 	fs := &filesystem{
 		devMinor: devMinor,
 		opts:     opts,
 		conn:     conn,
 	}
-
-	fs.VFSFilesystem().IncRef()
 	fuseFD.fs = fs
-
 	return fs, nil
 }
 
@@ -288,7 +284,7 @@ func (fs *filesystem) newRoot(ctx context.Context, creds *auth.Credentials, mode
 	i := &inode{fs: fs, nodeID: 1}
 	i.InodeAttrs.Init(ctx, creds, linux.UNNAMED_MAJOR, fs.devMinor, 1, linux.ModeDirectory|0755)
 	i.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
-	i.EnableLeakCheck()
+	i.InitRefs()
 
 	var d kernfs.Dentry
 	d.InitRoot(&fs.Filesystem, i)
@@ -301,7 +297,7 @@ func (fs *filesystem) newInode(ctx context.Context, nodeID uint64, attr linux.FU
 	i.InodeAttrs.Init(ctx, &creds, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.FileMode(attr.Mode))
 	atomic.StoreUint64(&i.size, attr.Size)
 	i.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
-	i.EnableLeakCheck()
+	i.InitRefs()
 	return i
 }
 
diff --git a/pkg/sentry/fsimpl/fuse/utils_test.go b/pkg/sentry/fsimpl/fuse/utils_test.go
index e1d9e3365..b2f4276b8 100644
--- a/pkg/sentry/fsimpl/fuse/utils_test.go
+++ b/pkg/sentry/fsimpl/fuse/utils_test.go
@@ -72,6 +72,7 @@ func newTestConnection(system *testutil.System, k *kernel.Kernel, maxActiveReque
 	if err != nil {
 		return nil, nil, err
 	}
+	fs.VFSFilesystem().Init(vfsObj, nil, fs)
 
 	return fs.conn, &fuseDev.vfsfd, nil
 }
diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go
index b59f62652..53bcc9986 100644
--- a/pkg/sentry/fsimpl/gofer/gofer.go
+++ b/pkg/sentry/fsimpl/gofer/gofer.go
@@ -1236,7 +1236,9 @@ func (d *dentry) IncRef() {
 	// d.refs may be 0 if d.fs.renameMu is locked, which serializes against
 	// d.checkCachingLocked().
 	r := atomic.AddInt64(&d.refs, 1)
-	refsvfs2.LogIncRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogIncRef(d, r)
+	}
 }
 
 // TryIncRef implements vfs.DentryImpl.TryIncRef.
@@ -1247,7 +1249,9 @@ func (d *dentry) TryIncRef() bool {
 			return false
 		}
 		if atomic.CompareAndSwapInt64(&d.refs, r, r+1) {
-			refsvfs2.LogTryIncRef(d, r+1)
+			if d.LogRefs() {
+				refsvfs2.LogTryIncRef(d, r+1)
+			}
 			return true
 		}
 	}
@@ -1267,7 +1271,9 @@ func (d *dentry) DecRef(ctx context.Context) {
 // responsible for ensuring that d.checkCachingLocked will be called later.
 func (d *dentry) decRefNoCaching() int64 {
 	r := atomic.AddInt64(&d.refs, -1)
-	refsvfs2.LogDecRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogDecRef(d, r)
+	}
 	if r < 0 {
 		panic("gofer.dentry.decRefNoCaching() called without holding a reference")
 	}
diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go
index 39b902a3e..435a21d77 100644
--- a/pkg/sentry/fsimpl/host/host.go
+++ b/pkg/sentry/fsimpl/host/host.go
@@ -126,8 +126,8 @@ func newInode(ctx context.Context, fs *filesystem, hostFD int, savable bool, fil
 		isTTY:    isTTY,
 		savable:  savable,
 	}
+	i.InitRefs()
 	i.CachedMappable.Init(hostFD)
-	i.EnableLeakCheck()
 
 	// If the hostFD can return EWOULDBLOCK when set to non-blocking, do so and
 	// handle blocking behavior in the sentry.
diff --git a/pkg/sentry/fsimpl/host/socket.go b/pkg/sentry/fsimpl/host/socket.go
index 8a447e29f..60acc367f 100644
--- a/pkg/sentry/fsimpl/host/socket.go
+++ b/pkg/sentry/fsimpl/host/socket.go
@@ -84,6 +84,8 @@ type ConnectedEndpoint struct {
 // init performs initialization required for creating new ConnectedEndpoints and
 // for restoring them.
 func (c *ConnectedEndpoint) init() *syserr.Error {
+	c.InitRefs()
+
 	family, err := syscall.GetsockoptInt(c.fd, syscall.SOL_SOCKET, syscall.SO_DOMAIN)
 	if err != nil {
 		return syserr.FromError(err)
@@ -132,7 +134,6 @@ func NewConnectedEndpoint(ctx context.Context, hostFD int, addr string, saveable
 
 	// ConnectedEndpointRefs start off with a single reference. We need two.
 	e.IncRef()
-	e.EnableLeakCheck()
 	return &e, nil
 }
 
@@ -376,8 +377,7 @@ func NewSCMEndpoint(ctx context.Context, hostFD int, queue *waiter.Queue, addr s
 		return nil, err
 	}
 
-	// ConnectedEndpointRefs start off with a single reference. We need two.
+	// e starts off with a single reference. We need two.
 	e.IncRef()
-	e.EnableLeakCheck()
 	return &e, nil
 }
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index d83c17f83..eac578f25 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -660,7 +660,7 @@ var _ Inode = (*StaticDirectory)(nil)
 func NewStaticDir(ctx context.Context, creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, perm linux.FileMode, children map[string]Inode, fdOpts GenericDirectoryFDOptions) Inode {
 	inode := &StaticDirectory{}
 	inode.Init(ctx, creds, devMajor, devMinor, ino, perm, fdOpts)
-	inode.EnableLeakCheck()
+	inode.InitRefs()
 
 	inode.OrderedChildren.Init(OrderedChildrenOptions{})
 	links := inode.OrderedChildren.Populate(children)
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go
index abb477c7d..c14abcff4 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs.go
@@ -222,7 +222,9 @@ func (d *Dentry) IncRef() {
 	// d.refs may be 0 if d.fs.mu is locked, which serializes against
 	// d.cacheLocked().
 	r := atomic.AddInt64(&d.refs, 1)
-	refsvfs2.LogIncRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogIncRef(d, r)
+	}
 }
 
 // TryIncRef implements vfs.DentryImpl.TryIncRef.
@@ -233,7 +235,9 @@ func (d *Dentry) TryIncRef() bool {
 			return false
 		}
 		if atomic.CompareAndSwapInt64(&d.refs, r, r+1) {
-			refsvfs2.LogTryIncRef(d, r+1)
+			if d.LogRefs() {
+				refsvfs2.LogTryIncRef(d, r+1)
+			}
 			return true
 		}
 	}
@@ -242,7 +246,9 @@ func (d *Dentry) TryIncRef() bool {
 // DecRef implements vfs.DentryImpl.DecRef.
 func (d *Dentry) DecRef(ctx context.Context) {
 	r := atomic.AddInt64(&d.refs, -1)
-	refsvfs2.LogDecRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogDecRef(d, r)
+	}
 	if r == 0 {
 		d.fs.mu.Lock()
 		d.cacheLocked(ctx)
@@ -254,7 +260,9 @@ func (d *Dentry) DecRef(ctx context.Context) {
 
 func (d *Dentry) decRefLocked(ctx context.Context) {
 	r := atomic.AddInt64(&d.refs, -1)
-	refsvfs2.LogDecRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogDecRef(d, r)
+	}
 	if r == 0 {
 		d.cacheLocked(ctx)
 	} else if r < 0 {
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_test.go b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
index 2418eec44..e63588e33 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs_test.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
@@ -109,7 +109,7 @@ func (fs *filesystem) newReadonlyDir(ctx context.Context, creds *auth.Credential
 	dir := &readonlyDir{}
 	dir.attrs.Init(ctx, creds, 0 /* devMajor */, 0 /* devMinor */, fs.NextIno(), linux.ModeDirectory|mode)
 	dir.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
-	dir.EnableLeakCheck()
+	dir.InitRefs()
 	dir.IncLinks(dir.OrderedChildren.Populate(contents))
 	return dir
 }
@@ -147,7 +147,7 @@ func (fs *filesystem) newDir(ctx context.Context, creds *auth.Credentials, mode
 	dir.fs = fs
 	dir.attrs.Init(ctx, creds, 0 /* devMajor */, 0 /* devMinor */, fs.NextIno(), linux.ModeDirectory|mode)
 	dir.OrderedChildren.Init(kernfs.OrderedChildrenOptions{Writable: true})
-	dir.EnableLeakCheck()
+	dir.InitRefs()
 
 	dir.IncLinks(dir.OrderedChildren.Populate(contents))
 	return dir
diff --git a/pkg/sentry/fsimpl/overlay/overlay.go b/pkg/sentry/fsimpl/overlay/overlay.go
index 73130bc8d..3492409b2 100644
--- a/pkg/sentry/fsimpl/overlay/overlay.go
+++ b/pkg/sentry/fsimpl/overlay/overlay.go
@@ -514,7 +514,9 @@ func (d *dentry) IncRef() {
 	// d.refs may be 0 if d.fs.renameMu is locked, which serializes against
 	// d.checkDropLocked().
 	r := atomic.AddInt64(&d.refs, 1)
-	refsvfs2.LogIncRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogIncRef(d, r)
+	}
 }
 
 // TryIncRef implements vfs.DentryImpl.TryIncRef.
@@ -525,7 +527,9 @@ func (d *dentry) TryIncRef() bool {
 			return false
 		}
 		if atomic.CompareAndSwapInt64(&d.refs, r, r+1) {
-			refsvfs2.LogTryIncRef(d, r+1)
+			if d.LogRefs() {
+				refsvfs2.LogTryIncRef(d, r+1)
+			}
 			return true
 		}
 	}
@@ -534,7 +538,9 @@ func (d *dentry) TryIncRef() bool {
 // DecRef implements vfs.DentryImpl.DecRef.
 func (d *dentry) DecRef(ctx context.Context) {
 	r := atomic.AddInt64(&d.refs, -1)
-	refsvfs2.LogDecRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogDecRef(d, r)
+	}
 	if r == 0 {
 		d.fs.renameMu.Lock()
 		d.checkDropLocked(ctx)
@@ -546,7 +552,9 @@ func (d *dentry) DecRef(ctx context.Context) {
 
 func (d *dentry) decRefLocked(ctx context.Context) {
 	r := atomic.AddInt64(&d.refs, -1)
-	refsvfs2.LogDecRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogDecRef(d, r)
+	}
 	if r == 0 {
 		d.checkDropLocked(ctx)
 	} else if r < 0 {
diff --git a/pkg/sentry/fsimpl/proc/subtasks.go b/pkg/sentry/fsimpl/proc/subtasks.go
index cb3c5e0fd..e001d5032 100644
--- a/pkg/sentry/fsimpl/proc/subtasks.go
+++ b/pkg/sentry/fsimpl/proc/subtasks.go
@@ -60,7 +60,7 @@ func (fs *filesystem) newSubtasks(task *kernel.Task, pidns *kernel.PIDNamespace,
 	// Note: credentials are overridden by taskOwnedInode.
 	subInode.InodeAttrs.Init(task, task.Credentials(), linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0555)
 	subInode.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
-	subInode.EnableLeakCheck()
+	subInode.InitRefs()
 
 	inode := &taskOwnedInode{Inode: subInode, owner: task}
 	return inode
diff --git a/pkg/sentry/fsimpl/proc/task.go b/pkg/sentry/fsimpl/proc/task.go
index 19011b010..dc46a09bc 100644
--- a/pkg/sentry/fsimpl/proc/task.go
+++ b/pkg/sentry/fsimpl/proc/task.go
@@ -91,7 +91,7 @@ func (fs *filesystem) newTaskInode(task *kernel.Task, pidns *kernel.PIDNamespace
 	taskInode := &taskInode{task: task}
 	// Note: credentials are overridden by taskOwnedInode.
 	taskInode.InodeAttrs.Init(task, task.Credentials(), linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0555)
-	taskInode.EnableLeakCheck()
+	taskInode.InitRefs()
 
 	inode := &taskOwnedInode{Inode: taskInode, owner: task}
 
diff --git a/pkg/sentry/fsimpl/proc/task_fds.go b/pkg/sentry/fsimpl/proc/task_fds.go
index d268b44be..3ec4471f5 100644
--- a/pkg/sentry/fsimpl/proc/task_fds.go
+++ b/pkg/sentry/fsimpl/proc/task_fds.go
@@ -128,7 +128,7 @@ func (fs *filesystem) newFDDirInode(task *kernel.Task) kernfs.Inode {
 		},
 	}
 	inode.InodeAttrs.Init(task, task.Credentials(), linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0555)
-	inode.EnableLeakCheck()
+	inode.InitRefs()
 	inode.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
 	return inode
 }
@@ -265,7 +265,7 @@ func (fs *filesystem) newFDInfoDirInode(task *kernel.Task) kernfs.Inode {
 		},
 	}
 	inode.InodeAttrs.Init(task, task.Credentials(), linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0555)
-	inode.EnableLeakCheck()
+	inode.InitRefs()
 	inode.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
 	return inode
 }
diff --git a/pkg/sentry/fsimpl/proc/tasks.go b/pkg/sentry/fsimpl/proc/tasks.go
index b81ea14bf..151d1f10d 100644
--- a/pkg/sentry/fsimpl/proc/tasks.go
+++ b/pkg/sentry/fsimpl/proc/tasks.go
@@ -83,7 +83,7 @@ func (fs *filesystem) newTasksInode(ctx context.Context, k *kernel.Kernel, pidns
 		cgroupControllers: cgroupControllers,
 	}
 	inode.InodeAttrs.Init(ctx, root, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0555)
-	inode.EnableLeakCheck()
+	inode.InitRefs()
 
 	inode.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
 	links := inode.OrderedChildren.Populate(contents)
diff --git a/pkg/sentry/fsimpl/sys/sys.go b/pkg/sentry/fsimpl/sys/sys.go
index 506a2a0f0..79bc3fe88 100644
--- a/pkg/sentry/fsimpl/sys/sys.go
+++ b/pkg/sentry/fsimpl/sys/sys.go
@@ -160,7 +160,7 @@ func (fs *filesystem) newDir(ctx context.Context, creds *auth.Credentials, mode
 	d := &dir{}
 	d.InodeAttrs.Init(ctx, creds, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0755)
 	d.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
-	d.EnableLeakCheck()
+	d.InitRefs()
 	d.IncLinks(d.OrderedChildren.Populate(contents))
 	return d
 }
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index 4ce859d57..85a3dfe20 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -402,7 +402,7 @@ func (i *inode) init(impl interface{}, fs *filesystem, kuid auth.KUID, kgid auth
 	i.mtime = now
 	// i.nlink initialized by caller
 	i.impl = impl
-	i.refs.EnableLeakCheck()
+	i.refs.InitRefs()
 }
 
 // incLinksLocked increments i's link count.
diff --git a/pkg/sentry/fsimpl/verity/verity.go b/pkg/sentry/fsimpl/verity/verity.go
index d24c839bb..faa862c55 100644
--- a/pkg/sentry/fsimpl/verity/verity.go
+++ b/pkg/sentry/fsimpl/verity/verity.go
@@ -380,7 +380,9 @@ func (fs *filesystem) newDentry() *dentry {
 // IncRef implements vfs.DentryImpl.IncRef.
 func (d *dentry) IncRef() {
 	r := atomic.AddInt64(&d.refs, 1)
-	refsvfs2.LogIncRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogIncRef(d, r)
+	}
 }
 
 // TryIncRef implements vfs.DentryImpl.TryIncRef.
@@ -391,7 +393,9 @@ func (d *dentry) TryIncRef() bool {
 			return false
 		}
 		if atomic.CompareAndSwapInt64(&d.refs, r, r+1) {
-			refsvfs2.LogTryIncRef(d, r+1)
+			if d.LogRefs() {
+				refsvfs2.LogTryIncRef(d, r+1)
+			}
 			return true
 		}
 	}
@@ -400,7 +404,9 @@ func (d *dentry) TryIncRef() bool {
 // DecRef implements vfs.DentryImpl.DecRef.
 func (d *dentry) DecRef(ctx context.Context) {
 	r := atomic.AddInt64(&d.refs, -1)
-	refsvfs2.LogDecRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogDecRef(d, r)
+	}
 	if r == 0 {
 		d.fs.renameMu.Lock()
 		d.checkDropLocked(ctx)
@@ -412,7 +418,9 @@ func (d *dentry) DecRef(ctx context.Context) {
 
 func (d *dentry) decRefLocked(ctx context.Context) {
 	r := atomic.AddInt64(&d.refs, -1)
-	refsvfs2.LogDecRef(d, r)
+	if d.LogRefs() {
+		refsvfs2.LogDecRef(d, r)
+	}
 	if r == 0 {
 		d.checkDropLocked(ctx)
 	} else if r < 0 {