Add leak checking to vfs2 structures that cannot use the refs_vfs2 template.

Updates #1486.

PiperOrigin-RevId: 338832085

3 files changed, 41 insertions, 0 deletions

diff --git a/pkg/sentry/fsimpl/verity/BUILD b/pkg/sentry/fsimpl/verity/BUILD
index 0ca750281..ab117ee9d 100644
--- a/pkg/sentry/fsimpl/verity/BUILD
+++ b/pkg/sentry/fsimpl/verity/BUILD
@@ -6,6 +6,7 @@ go_library(
     name = "verity",
     srcs = [
         "filesystem.go",
+        "save_restore.go",
         "verity.go",
     ],
     visibility = ["//pkg/sentry:internal"],
@@ -15,6 +16,7 @@ go_library(
         "//pkg/fspath",
         "//pkg/marshal/primitive",
         "//pkg/merkletree",
+        "//pkg/refsvfs2",
         "//pkg/sentry/arch",
         "//pkg/sentry/fs/lock",
         "//pkg/sentry/kernel",
diff --git a/pkg/sentry/fsimpl/verity/save_restore.go b/pkg/sentry/fsimpl/verity/save_restore.go
new file mode 100644
index 000000000..4a161163c
--- /dev/null
+++ b/pkg/sentry/fsimpl/verity/save_restore.go
@@ -0,0 +1,27 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package verity
+
+import (
+	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/refsvfs2"
+)
+
+func (d *dentry) afterLoad() {
+	if refsvfs2.LeakCheckEnabled() && atomic.LoadInt64(&d.refs) != -1 {
+		refsvfs2.Register(d, "verity.dentry")
+	}
+}
diff --git a/pkg/sentry/fsimpl/verity/verity.go b/pkg/sentry/fsimpl/verity/verity.go
index b0377ed71..d201c0dcf 100644
--- a/pkg/sentry/fsimpl/verity/verity.go
+++ b/pkg/sentry/fsimpl/verity/verity.go
@@ -31,6 +31,7 @@ import (
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/marshal/primitive"
 	"gvisor.dev/gvisor/pkg/merkletree"
+	"gvisor.dev/gvisor/pkg/refsvfs2"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
@@ -331,6 +332,9 @@ func (fs *filesystem) newDentry() *dentry {
 		fs: fs,
 	}
 	d.vfsd.Init(d)
+	if refsvfs2.LeakCheckEnabled() {
+		refsvfs2.Register(d, "verity.dentry")
+	}
 	return d
 }
 
@@ -393,6 +397,9 @@ func (d *dentry) destroyLocked(ctx context.Context) {
 	if d.lowerVD.Ok() {
 		d.lowerVD.DecRef(ctx)
 	}
+	if refsvfs2.LeakCheckEnabled() {
+		refsvfs2.Unregister(d, "verity.dentry")
+	}
 
 	if d.lowerMerkleVD.Ok() {
 		d.lowerMerkleVD.DecRef(ctx)
@@ -412,6 +419,11 @@ func (d *dentry) destroyLocked(ctx context.Context) {
 	}
 }
 
+// LeakMessage implements refsvfs2.CheckedObject.LeakMessage.
+func (d *dentry) LeakMessage() string {
+	return fmt.Sprintf("[verity.dentry %p] reference count of %d instead of -1", d, atomic.LoadInt64(&d.refs))
+}
+
 // InotifyWithParent implements vfs.DentryImpl.InotifyWithParent.
 func (d *dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, et vfs.EventType) {
 	//TODO(b/159261227): Implement InotifyWithParent.