Use new reference count utility throughout gvisor.

This uses the refs_vfs2 template in vfs2 as well as objects common to vfs1 and
vfs2. Note that vfs1-only refcounts are not replaced, since vfs1 will be deleted
soon anyway.

The following structs now use the new tool, with leak check enabled:
devpts:rootInode
fuse:inode
kernfs:Dentry
kernfs:dir
kernfs:readonlyDir
kernfs:StaticDirectory
proc:fdDirInode
proc:fdInfoDirInode
proc:subtasksInode
proc:taskInode
proc:tasksInode
vfs:FileDescription
vfs:MountNamespace
vfs:Filesystem
sys:dir
kernel:FSContext
kernel:ProcessGroup
kernel:Session
shm:Shm
mm:aioMappable
mm:SpecialMappable
transport:queue

And the following use the template, but because they currently are not leak
checked, a TODO is left instead of enabling leak check in this patch:
kernel:FDTable
tun:tunEndpoint

Updates #1486.

PiperOrigin-RevId: 328460377

2 files changed, 22 insertions, 0 deletions

diff --git a/pkg/sentry/fsimpl/devpts/BUILD b/pkg/sentry/fsimpl/devpts/BUILD
index 93512c9b6..3f64fab3a 100644
--- a/pkg/sentry/fsimpl/devpts/BUILD
+++ b/pkg/sentry/fsimpl/devpts/BUILD
@@ -1,7 +1,19 @@
 load("//tools:defs.bzl", "go_library", "go_test")
+load("//tools/go_generics:defs.bzl", "go_template_instance")
 
 licenses(["notice"])
 
+go_template_instance(
+    name = "root_inode_refs",
+    out = "root_inode_refs.go",
+    package = "devpts",
+    prefix = "rootInode",
+    template = "//pkg/refs_vfs2:refs_template",
+    types = {
+        "T": "rootInode",
+    },
+)
+
 go_library(
     name = "devpts",
     srcs = [
@@ -9,6 +21,7 @@ go_library(
         "line_discipline.go",
         "master.go",
         "queue.go",
+        "root_inode_refs.go",
         "slave.go",
         "terminal.go",
     ],
@@ -16,6 +29,8 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/log",
+        "//pkg/refs",
         "//pkg/safemem",
         "//pkg/sentry/arch",
         "//pkg/sentry/fs/lock",
diff --git a/pkg/sentry/fsimpl/devpts/devpts.go b/pkg/sentry/fsimpl/devpts/devpts.go
index 3f3a099bd..0eaff9087 100644
--- a/pkg/sentry/fsimpl/devpts/devpts.go
+++ b/pkg/sentry/fsimpl/devpts/devpts.go
@@ -83,6 +83,7 @@ func (fstype FilesystemType) newFilesystem(vfsObj *vfs.VirtualFilesystem, creds
 	}
 	root.InodeAttrs.Init(creds, linux.UNNAMED_MAJOR, devMinor, 1, linux.ModeDirectory|0555)
 	root.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
+	root.EnableLeakCheck()
 	root.dentry.Init(root)
 
 	// Construct the pts master inode and dentry. Linux always uses inode
@@ -110,6 +111,7 @@ func (fs *filesystem) Release(ctx context.Context) {
 
 // rootInode is the root directory inode for the devpts mounts.
 type rootInode struct {
+	rootInodeRefs
 	kernfs.AlwaysValid
 	kernfs.InodeAttrs
 	kernfs.InodeDirectoryNoNewChildren
@@ -233,3 +235,8 @@ func (i *rootInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback,
 	}
 	return offset, nil
 }
+
+// DecRef implements kernfs.Inode.
+func (i *rootInode) DecRef(context.Context) {
+	i.rootInodeRefs.DecRef(i.Destroy)
+}