3 files changed, 26 insertions, 16 deletions
diff --git a/pkg/sentry/fsimpl/sys/BUILD b/pkg/sentry/fsimpl/sys/BUILD
index a741e2bb6..1b548ccd4 100644
--- a/pkg/sentry/fsimpl/sys/BUILD
+++ b/pkg/sentry/fsimpl/sys/BUILD
@@ -29,6 +29,6 @@ go_test(
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/vfs",
-        "@com_github_google_go-cmp//cmp:go_default_library",
+        "@com_github_google_go_cmp//cmp:go_default_library",
     ],
 )
diff --git a/pkg/sentry/fsimpl/sys/sys.go b/pkg/sentry/fsimpl/sys/sys.go
index 0af373604..0401726b6 100644
--- a/pkg/sentry/fsimpl/sys/sys.go
+++ b/pkg/sentry/fsimpl/sys/sys.go
@@ -30,6 +30,7 @@ import (
 
 // Name is the default filesystem name.
 const Name = "sysfs"
+const defaultSysDirMode = linux.FileMode(0755)
 
 // FilesystemType implements vfs.FilesystemType.
 type FilesystemType struct{}
@@ -57,9 +58,6 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 		devMinor: devMinor,
 	}
 	fs.VFSFilesystem().Init(vfsObj, &fsType, fs)
-	k := kernel.KernelFromContext(ctx)
-	maxCPUCores := k.ApplicationCores()
-	defaultSysDirMode := linux.FileMode(0755)
 
 	root := fs.newDir(creds, defaultSysDirMode, map[string]*kernfs.Dentry{
 		"block": fs.newDir(creds, defaultSysDirMode, nil),
@@ -70,11 +68,7 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 		"dev": fs.newDir(creds, defaultSysDirMode, nil),
 		"devices": fs.newDir(creds, defaultSysDirMode, map[string]*kernfs.Dentry{
 			"system": fs.newDir(creds, defaultSysDirMode, map[string]*kernfs.Dentry{
-				"cpu": fs.newDir(creds, defaultSysDirMode, map[string]*kernfs.Dentry{
-					"online":   fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)),
-					"possible": fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)),
-					"present":  fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)),
-				}),
+				"cpu": cpuDir(ctx, fs, creds),
 			}),
 		}),
 		"firmware": fs.newDir(creds, defaultSysDirMode, nil),
@@ -86,10 +80,24 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 	return fs.VFSFilesystem(), root.VFSDentry(), nil
 }
 
+func cpuDir(ctx context.Context, fs *filesystem, creds *auth.Credentials) *kernfs.Dentry {
+	k := kernel.KernelFromContext(ctx)
+	maxCPUCores := k.ApplicationCores()
+	children := map[string]*kernfs.Dentry{
+		"online":   fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)),
+		"possible": fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)),
+		"present":  fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)),
+	}
+	for i := uint(0); i < maxCPUCores; i++ {
+		children[fmt.Sprintf("cpu%d", i)] = fs.newDir(creds, linux.FileMode(0555), nil)
+	}
+	return fs.newDir(creds, defaultSysDirMode, children)
+}
+
 // Release implements vfs.FilesystemImpl.Release.
-func (fs *filesystem) Release() {
+func (fs *filesystem) Release(ctx context.Context) {
 	fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor)
-	fs.Filesystem.Release()
+	fs.Filesystem.Release(ctx)
 }
 
 // dir implements kernfs.Inode.
@@ -98,8 +106,10 @@ type dir struct {
 	kernfs.InodeNoDynamicLookup
 	kernfs.InodeNotSymlink
 	kernfs.InodeDirectoryNoNewChildren
-
 	kernfs.OrderedChildren
+
+	locks vfs.FileLocks
+
 	dentry kernfs.Dentry
 }
 
@@ -121,7 +131,7 @@ func (*dir) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.Set
 
 // Open implements kernfs.Inode.Open.
 func (d *dir) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
-	fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &d.OrderedChildren, &opts)
+	fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &d.OrderedChildren, &d.locks, &opts)
 	if err != nil {
 		return nil, err
 	}
@@ -136,7 +146,7 @@ type cpuFile struct {
 
 // Generate implements vfs.DynamicBytesSource.Generate.
 func (c *cpuFile) Generate(ctx context.Context, buf *bytes.Buffer) error {
-	fmt.Fprintf(buf, "0-%d", c.maxCores-1)
+	fmt.Fprintf(buf, "0-%d\n", c.maxCores-1)
 	return nil
 }
 
diff --git a/pkg/sentry/fsimpl/sys/sys_test.go b/pkg/sentry/fsimpl/sys/sys_test.go
index 4b3602d47..9fd38b295 100644
--- a/pkg/sentry/fsimpl/sys/sys_test.go
+++ b/pkg/sentry/fsimpl/sys/sys_test.go
@@ -51,7 +51,7 @@ func TestReadCPUFile(t *testing.T) {
 	k := kernel.KernelFromContext(s.Ctx)
 	maxCPUCores := k.ApplicationCores()
 
-	expected := fmt.Sprintf("0-%d", maxCPUCores-1)
+	expected := fmt.Sprintf("0-%d\n", maxCPUCores-1)
 
 	for _, fname := range []string{"online", "possible", "present"} {
 		pop := s.PathOpAtRoot(fmt.Sprintf("devices/system/cpu/%s", fname))
@@ -59,7 +59,7 @@ func TestReadCPUFile(t *testing.T) {
 		if err != nil {
 			t.Fatalf("OpenAt(pop:%+v) = %+v failed: %v", pop, fd, err)
 		}
-		defer fd.DecRef()
+		defer fd.DecRef(s.Ctx)
 		content, err := s.ReadToEnd(fd)
 		if err != nil {
 			t.Fatalf("Read failed: %v", err)