Merge release-20200818.0-124-g2202812e0 (automated)

33 files changed, 128 insertions, 110 deletions

diff --git a/pkg/abi/linux/linux_abi_autogen_unsafe.go b/pkg/abi/linux/linux_abi_autogen_unsafe.go
index 8b584fd2a..ea9eba10f 100644
--- a/pkg/abi/linux/linux_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_abi_autogen_unsafe.go
@@ -155,7 +155,7 @@ func (s *Statx) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (s *Statx) Packed() bool {
-    return s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed()
+    return s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -181,7 +181,7 @@ func (s *Statx) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (s *Statx) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() {
+    if !s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         s.MarshalBytes(buf) // escapes: fallback.
@@ -237,7 +237,7 @@ func (s *Statx) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (s *Statx) WriteTo(writer io.Writer) (int64, error) {
-    if !s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() {
+    if !s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, s.SizeBytes())
         s.MarshalBytes(buf)
@@ -712,7 +712,7 @@ func (f *FUSEHeaderIn) CopyIn(task marshal.Task, addr usermem.Addr) (int, error)
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (f *FUSEHeaderIn) WriteTo(writer io.Writer) (int64, error) {
-    if !f.Unique.Packed() && f.Opcode.Packed() {
+    if !f.Opcode.Packed() && f.Unique.Packed() {
         // Type FUSEHeaderIn doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, f.SizeBytes())
         f.MarshalBytes(buf)
@@ -2211,7 +2211,7 @@ func (i *IPTIP) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (i *IPTIP) Packed() bool {
-    return i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed()
+    return i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -2226,7 +2226,7 @@ func (i *IPTIP) MarshalUnsafe(dst []byte) {
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
 func (i *IPTIP) UnmarshalUnsafe(src []byte) {
-    if i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+    if i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
         safecopy.CopyOut(unsafe.Pointer(i), src)
     } else {
         // Type IPTIP doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -2237,7 +2237,7 @@ func (i *IPTIP) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (i *IPTIP) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IPTIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         i.MarshalBytes(buf) // escapes: fallback.
@@ -2267,7 +2267,7 @@ func (i *IPTIP) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IPTIP doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -3058,7 +3058,7 @@ func (i *IP6TEntry) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (i *IP6TEntry) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !i.Counters.Packed() && i.IPv6.Packed() {
+    if !i.IPv6.Packed() && i.Counters.Packed() {
         // Type IP6TEntry doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -3225,7 +3225,7 @@ func (i *IP6TIP) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (i *IP6TIP) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IP6TIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         i.MarshalBytes(buf) // escapes: fallback.
@@ -3255,7 +3255,7 @@ func (i *IP6TIP) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (i *IP6TIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+    if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
         // Type IP6TIP doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -3281,7 +3281,7 @@ func (i *IP6TIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (i *IP6TIP) WriteTo(writer io.Writer) (int64, error) {
-    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+    if !i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
         // Type IP6TIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, i.SizeBytes())
         i.MarshalBytes(buf)
diff --git a/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go b/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
index c49b2aecc..4c1b96265 100644
--- a/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
@@ -303,7 +303,7 @@ func (s *Stat) MarshalUnsafe(dst []byte) {
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
 func (s *Stat) UnmarshalUnsafe(src []byte) {
-    if s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
+    if s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
         safecopy.CopyOut(unsafe.Pointer(s), src)
     } else {
         // Type Stat doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -314,7 +314,7 @@ func (s *Stat) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (s *Stat) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+    if !s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         s.MarshalBytes(buf) // escapes: fallback.
@@ -344,7 +344,7 @@ func (s *Stat) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
+    if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -370,7 +370,7 @@ func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (s *Stat) WriteTo(writer io.Writer) (int64, error) {
-    if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+    if !s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, s.SizeBytes())
         s.MarshalBytes(buf)
diff --git a/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go b/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
index 932f78be4..8a1748313 100644
--- a/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
@@ -295,12 +295,12 @@ func (s *Stat) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (s *Stat) Packed() bool {
-    return s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed()
+    return s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
 func (s *Stat) MarshalUnsafe(dst []byte) {
-    if s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+    if s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
         safecopy.CopyIn(dst, unsafe.Pointer(s))
     } else {
         // Type Stat doesn't have a packed layout in memory, fallback to MarshalBytes.
@@ -351,7 +351,7 @@ func (s *Stat) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+    if !s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -377,7 +377,7 @@ func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (s *Stat) WriteTo(writer io.Writer) (int64, error) {
-    if !s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
+    if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, s.SizeBytes())
         s.MarshalBytes(buf)
diff --git a/pkg/fd/fd.go b/pkg/fd/fd.go
index 83bcfe220..cc6b0cdf1 100644
--- a/pkg/fd/fd.go
+++ b/pkg/fd/fd.go
@@ -49,7 +49,7 @@ func fixCount(n int, err error) (int, error) {
 
 // Read implements io.Reader.
 func (r *ReadWriter) Read(b []byte) (int, error) {
-	c, err := fixCount(syscall.Read(int(atomic.LoadInt64(&r.fd)), b))
+	c, err := fixCount(syscall.Read(r.FD(), b))
 	if c == 0 && len(b) > 0 && err == nil {
 		return 0, io.EOF
 	}
@@ -62,7 +62,7 @@ func (r *ReadWriter) Read(b []byte) (int, error) {
 func (r *ReadWriter) ReadAt(b []byte, off int64) (c int, err error) {
 	for len(b) > 0 {
 		var m int
-		m, err = fixCount(syscall.Pread(int(atomic.LoadInt64(&r.fd)), b, off))
+		m, err = fixCount(syscall.Pread(r.FD(), b, off))
 		if m == 0 && err == nil {
 			return c, io.EOF
 		}
@@ -82,7 +82,7 @@ func (r *ReadWriter) Write(b []byte) (int, error) {
 	var n, remaining int
 	for remaining = len(b); remaining > 0; {
 		woff := len(b) - remaining
-		n, err = syscall.Write(int(atomic.LoadInt64(&r.fd)), b[woff:])
+		n, err = syscall.Write(r.FD(), b[woff:])
 
 		if n > 0 {
 			// syscall.Write wrote some bytes. This is the common case.
@@ -110,7 +110,7 @@ func (r *ReadWriter) Write(b []byte) (int, error) {
 func (r *ReadWriter) WriteAt(b []byte, off int64) (c int, err error) {
 	for len(b) > 0 {
 		var m int
-		m, err = fixCount(syscall.Pwrite(int(atomic.LoadInt64(&r.fd)), b, off))
+		m, err = fixCount(syscall.Pwrite(r.FD(), b, off))
 		if err != nil {
 			break
 		}
@@ -121,6 +121,16 @@ func (r *ReadWriter) WriteAt(b []byte, off int64) (c int, err error) {
 	return
 }
 
+// FD returns the owned file descriptor. Ownership remains unchanged.
+func (r *ReadWriter) FD() int {
+	return int(atomic.LoadInt64(&r.fd))
+}
+
+// String implements Stringer.String().
+func (r *ReadWriter) String() string {
+	return fmt.Sprintf("FD: %d", r.FD())
+}
+
 // FD owns a host file descriptor.
 //
 // It is similar to os.File, with a few important distinctions:
@@ -167,6 +177,23 @@ func NewFromFile(file *os.File) (*FD, error) {
 	return New(fd), nil
 }
 
+// NewFromFiles creates new FDs for each file in the slice.
+func NewFromFiles(files []*os.File) ([]*FD, error) {
+	rv := make([]*FD, 0, len(files))
+	for _, f := range files {
+		new, err := NewFromFile(f)
+		if err != nil {
+			// Cleanup on error.
+			for _, fd := range rv {
+				fd.Close()
+			}
+			return nil, err
+		}
+		rv = append(rv, new)
+	}
+	return rv, nil
+}
+
 // Open is equivalent to open(2).
 func Open(path string, openmode int, perm uint32) (*FD, error) {
 	f, err := syscall.Open(path, openmode|syscall.O_LARGEFILE, perm)
@@ -204,11 +231,6 @@ func (f *FD) Release() int {
 	return int(atomic.SwapInt64(&f.fd, -1))
 }
 
-// FD returns the file descriptor owned by FD. FD retains ownership.
-func (f *FD) FD() int {
-	return int(atomic.LoadInt64(&f.fd))
-}
-
 // File converts the FD to an os.File.
 //
 // FD does not transfer ownership of the file descriptor (it will be
@@ -219,7 +241,7 @@ func (f *FD) FD() int {
 // This operation is somewhat expensive, so care should be taken to minimize
 // its use.
 func (f *FD) File() (*os.File, error) {
-	fd, err := syscall.Dup(int(atomic.LoadInt64(&f.fd)))
+	fd, err := syscall.Dup(f.FD())
 	if err != nil {
 		return nil, err
 	}
diff --git a/pkg/sentry/control/proc.go b/pkg/sentry/control/proc.go
index dfa936563..668f47802 100644
--- a/pkg/sentry/control/proc.go
+++ b/pkg/sentry/control/proc.go
@@ -23,8 +23,8 @@ import (
 	"text/tabwriter"
 	"time"
 
-	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/sentry/fdimport"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/host"
@@ -203,27 +203,17 @@ func (proc *Proc) execAsync(args *ExecArgs) (*kernel.ThreadGroup, kernel.ThreadI
 	}
 	initArgs.Filename = resolved
 
-	fds := make([]int, len(args.FilePayload.Files))
-	for i, file := range args.FilePayload.Files {
-		if kernel.VFS2Enabled {
-			// Need to dup to remove ownership from os.File.
-			dup, err := unix.Dup(int(file.Fd()))
-			if err != nil {
-				return nil, 0, nil, nil, fmt.Errorf("duplicating payload files: %w", err)
-			}
-			fds[i] = dup
-		} else {
-			// VFS1 dups the file on import.
-			fds[i] = int(file.Fd())
-		}
+	fds, err := fd.NewFromFiles(args.Files)
+	if err != nil {
+		return nil, 0, nil, nil, fmt.Errorf("duplicating payload files: %w", err)
 	}
+	defer func() {
+		for _, fd := range fds {
+			_ = fd.Close()
+		}
+	}()
 	ttyFile, ttyFileVFS2, err := fdimport.Import(ctx, fdTable, args.StdioIsPty, fds)
 	if err != nil {
-		if kernel.VFS2Enabled {
-			for _, fd := range fds {
-				unix.Close(fd)
-			}
-		}
 		return nil, 0, nil, nil, err
 	}
 
diff --git a/pkg/sentry/fdimport/fdimport.go b/pkg/sentry/fdimport/fdimport.go
index 1b7cb94c0..314661475 100644
--- a/pkg/sentry/fdimport/fdimport.go
+++ b/pkg/sentry/fdimport/fdimport.go
@@ -18,6 +18,7 @@ import (
 	"fmt"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/host"
 	hostvfs2 "gvisor.dev/gvisor/pkg/sentry/fsimpl/host"
@@ -27,8 +28,9 @@ import (
 
 // Import imports a slice of FDs into the given FDTable. If console is true,
 // sets up TTY for the first 3 FDs in the slice representing stdin, stdout,
-// stderr. Upon success, Import takes ownership of all FDs.
-func Import(ctx context.Context, fdTable *kernel.FDTable, console bool, fds []int) (*host.TTYFileOperations, *hostvfs2.TTYFileDescription, error) {
+// stderr. Used FDs are either closed or released. It's safe for the caller to
+// close any remaining files upon return.
+func Import(ctx context.Context, fdTable *kernel.FDTable, console bool, fds []*fd.FD) (*host.TTYFileOperations, *hostvfs2.TTYFileDescription, error) {
 	if kernel.VFS2Enabled {
 		ttyFile, err := importVFS2(ctx, fdTable, console, fds)
 		return nil, ttyFile, err
@@ -37,7 +39,7 @@ func Import(ctx context.Context, fdTable *kernel.FDTable, console bool, fds []in
 	return ttyFile, nil, err
 }
 
-func importFS(ctx context.Context, fdTable *kernel.FDTable, console bool, fds []int) (*host.TTYFileOperations, error) {
+func importFS(ctx context.Context, fdTable *kernel.FDTable, console bool, fds []*fd.FD) (*host.TTYFileOperations, error) {
 	var ttyFile *fs.File
 	for appFD, hostFD := range fds {
 		var appFile *fs.File
@@ -46,11 +48,12 @@ func importFS(ctx context.Context, fdTable *kernel.FDTable, console bool, fds []
 			// Import the file as a host TTY file.
 			if ttyFile == nil {
 				var err error
-				appFile, err = host.ImportFile(ctx, hostFD, true /* isTTY */)
+				appFile, err = host.ImportFile(ctx, hostFD.FD(), true /* isTTY */)
 				if err != nil {
 					return nil, err
 				}
 				defer appFile.DecRef(ctx)
+				_ = hostFD.Close() // FD is dup'd i ImportFile.
 
 				// Remember this in the TTY file, as we will
 				// use it for the other stdio FDs.
@@ -65,11 +68,12 @@ func importFS(ctx context.Context, fdTable *kernel.FDTable, console bool, fds []
 		} else {
 			// Import the file as a regular host file.
 			var err error
-			appFile, err = host.ImportFile(ctx, hostFD, false /* isTTY */)
+			appFile, err = host.ImportFile(ctx, hostFD.FD(), false /* isTTY */)
 			if err != nil {
 				return nil, err
 			}
 			defer appFile.DecRef(ctx)
+			_ = hostFD.Close() // FD is dup'd i ImportFile.
 		}
 
 		// Add the file to the FD map.
@@ -84,7 +88,7 @@ func importFS(ctx context.Context, fdTable *kernel.FDTable, console bool, fds []
 	return ttyFile.FileOperations.(*host.TTYFileOperations), nil
 }
 
-func importVFS2(ctx context.Context, fdTable *kernel.FDTable, console bool, stdioFDs []int) (*hostvfs2.TTYFileDescription, error) {
+func importVFS2(ctx context.Context, fdTable *kernel.FDTable, console bool, stdioFDs []*fd.FD) (*hostvfs2.TTYFileDescription, error) {
 	k := kernel.KernelFromContext(ctx)
 	if k == nil {
 		return nil, fmt.Errorf("cannot find kernel from context")
@@ -98,11 +102,12 @@ func importVFS2(ctx context.Context, fdTable *kernel.FDTable, console bool, stdi
 			// Import the file as a host TTY file.
 			if ttyFile == nil {
 				var err error
-				appFile, err = hostvfs2.ImportFD(ctx, k.HostMount(), hostFD, true /* isTTY */)
+				appFile, err = hostvfs2.ImportFD(ctx, k.HostMount(), hostFD.FD(), true /* isTTY */)
 				if err != nil {
 					return nil, err
 				}
 				defer appFile.DecRef(ctx)
+				hostFD.Release() // FD is transfered to host FD.
 
 				// Remember this in the TTY file, as we will use it for the other stdio
 				// FDs.
@@ -115,11 +120,12 @@ func importVFS2(ctx context.Context, fdTable *kernel.FDTable, console bool, stdi
 			}
 		} else {
 			var err error
-			appFile, err = hostvfs2.ImportFD(ctx, k.HostMount(), hostFD, false /* isTTY */)
+			appFile, err = hostvfs2.ImportFD(ctx, k.HostMount(), hostFD.FD(), false /* isTTY */)
 			if err != nil {
 				return nil, err
 			}
 			defer appFile.DecRef(ctx)
+			hostFD.Release() // FD is transfered to host FD.
 		}
 
 		if err := fdTable.NewFDAtVFS2(ctx, int32(appFD), appFile, kernel.FDFlags{}); err != nil {
diff --git a/pkg/sentry/fsimpl/devpts/root_inode_refs.go b/pkg/sentry/fsimpl/devpts/root_inode_refs.go
index b860819f0..051801202 100644
--- a/pkg/sentry/fsimpl/devpts/root_inode_refs.go
+++ b/pkg/sentry/fsimpl/devpts/root_inode_refs.go
@@ -1,12 +1,12 @@
 package devpts
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/fuse/inode_refs.go b/pkg/sentry/fsimpl/fuse/inode_refs.go
index 646042846..6b9456e1d 100644
--- a/pkg/sentry/fsimpl/fuse/inode_refs.go
+++ b/pkg/sentry/fsimpl/fuse/inode_refs.go
@@ -1,12 +1,12 @@
 package fuse
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/host/connected_endpoint_refs.go b/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
index 670166c76..babb3f664 100644
--- a/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
+++ b/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
@@ -1,12 +1,12 @@
 package host
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/host/inode_refs.go b/pkg/sentry/fsimpl/host/inode_refs.go
index 49c57c113..17f90ce4a 100644
--- a/pkg/sentry/fsimpl/host/inode_refs.go
+++ b/pkg/sentry/fsimpl/host/inode_refs.go
@@ -1,12 +1,12 @@
 package host
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/kernfs/dentry_refs.go b/pkg/sentry/fsimpl/kernfs/dentry_refs.go
index 0269851c9..79863b3bc 100644
--- a/pkg/sentry/fsimpl/kernfs/dentry_refs.go
+++ b/pkg/sentry/fsimpl/kernfs/dentry_refs.go
@@ -1,12 +1,12 @@
 package kernfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/kernfs/static_directory_refs.go b/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
index 866620ef9..478b04bdd 100644
--- a/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
+++ b/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
@@ -1,12 +1,12 @@
 package kernfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go b/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
index 84c03e6cd..9431c1506 100644
--- a/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
@@ -1,12 +1,12 @@
 package proc
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go b/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
index 5b3c7cd1c..872b20eb0 100644
--- a/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
@@ -1,12 +1,12 @@
 package proc
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go b/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
index 3091deb89..c6d9b3522 100644
--- a/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
@@ -1,12 +1,12 @@
 package proc
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/task_inode_refs.go b/pkg/sentry/fsimpl/proc/task_inode_refs.go
index 5833527c5..714488450 100644
--- a/pkg/sentry/fsimpl/proc/task_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/task_inode_refs.go
@@ -1,12 +1,12 @@
 package proc
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/tasks_inode_refs.go b/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
index 0961dd629..22d9cc488 100644
--- a/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
@@ -1,12 +1,12 @@
 package proc
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/sys/dir_refs.go b/pkg/sentry/fsimpl/sys/dir_refs.go
index 718d542eb..89609b198 100644
--- a/pkg/sentry/fsimpl/sys/dir_refs.go
+++ b/pkg/sentry/fsimpl/sys/dir_refs.go
@@ -1,12 +1,12 @@
 package sys
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/tmpfs/inode_refs.go b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
index 5ec208d9e..dbf0b2766 100644
--- a/pkg/sentry/fsimpl/tmpfs/inode_refs.go
+++ b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
@@ -1,12 +1,12 @@
 package tmpfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/fd_table_refs.go b/pkg/sentry/kernel/fd_table_refs.go
index 9330e37e4..ecba138ac 100644
--- a/pkg/sentry/kernel/fd_table_refs.go
+++ b/pkg/sentry/kernel/fd_table_refs.go
@@ -1,12 +1,12 @@
 package kernel
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/fs_context_refs.go b/pkg/sentry/kernel/fs_context_refs.go
index e2280f400..fb2fde971 100644
--- a/pkg/sentry/kernel/fs_context_refs.go
+++ b/pkg/sentry/kernel/fs_context_refs.go
@@ -1,12 +1,12 @@
 package kernel
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/process_group_refs.go b/pkg/sentry/kernel/process_group_refs.go
index 832a99d66..4ed6e6458 100644
--- a/pkg/sentry/kernel/process_group_refs.go
+++ b/pkg/sentry/kernel/process_group_refs.go
@@ -1,12 +1,12 @@
 package kernel
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/session_refs.go b/pkg/sentry/kernel/session_refs.go
index 850f56d3a..f2e1bb797 100644
--- a/pkg/sentry/kernel/session_refs.go
+++ b/pkg/sentry/kernel/session_refs.go
@@ -1,12 +1,12 @@
 package kernel
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/shm/shm_refs.go b/pkg/sentry/kernel/shm/shm_refs.go
index 35f74eb6c..51e07d0b3 100644
--- a/pkg/sentry/kernel/shm/shm_refs.go
+++ b/pkg/sentry/kernel/shm/shm_refs.go
@@ -1,12 +1,12 @@
 package shm
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/mm/aio_mappable_refs.go b/pkg/sentry/mm/aio_mappable_refs.go
index d4f278400..b99909f07 100644
--- a/pkg/sentry/mm/aio_mappable_refs.go
+++ b/pkg/sentry/mm/aio_mappable_refs.go
@@ -1,12 +1,12 @@
 package mm
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/mm/special_mappable_refs.go b/pkg/sentry/mm/special_mappable_refs.go
index 2a348bacf..035bbe690 100644
--- a/pkg/sentry/mm/special_mappable_refs.go
+++ b/pkg/sentry/mm/special_mappable_refs.go
@@ -1,12 +1,12 @@
 package mm
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/platform/ring0/defs_impl_arm64.go b/pkg/sentry/platform/ring0/defs_impl_arm64.go
index 8ebfbfdb6..424b66f76 100644
--- a/pkg/sentry/platform/ring0/defs_impl_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_arm64.go
@@ -1,10 +1,10 @@
 package ring0
 
 import (
+	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
 
 	"fmt"
-	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/usermem"
 	"io"
 	"reflect"
diff --git a/pkg/sentry/socket/unix/socket_refs.go b/pkg/sentry/socket/unix/socket_refs.go
index a0e5d1393..dababb85f 100644
--- a/pkg/sentry/socket/unix/socket_refs.go
+++ b/pkg/sentry/socket/unix/socket_refs.go
@@ -1,12 +1,12 @@
 package unix
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/socket/unix/transport/queue_refs.go b/pkg/sentry/socket/unix/transport/queue_refs.go
index 21d43fc24..0d4e34988 100644
--- a/pkg/sentry/socket/unix/transport/queue_refs.go
+++ b/pkg/sentry/socket/unix/transport/queue_refs.go
@@ -1,12 +1,12 @@
 package transport
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/file_description_refs.go b/pkg/sentry/vfs/file_description_refs.go
index ebc089b4c..bdd7e6554 100644
--- a/pkg/sentry/vfs/file_description_refs.go
+++ b/pkg/sentry/vfs/file_description_refs.go
@@ -1,12 +1,12 @@
 package vfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/filesystem_refs.go b/pkg/sentry/vfs/filesystem_refs.go
index 32f21c044..38a9a986f 100644
--- a/pkg/sentry/vfs/filesystem_refs.go
+++ b/pkg/sentry/vfs/filesystem_refs.go
@@ -1,12 +1,12 @@
 package vfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/mount_namespace_refs.go b/pkg/sentry/vfs/mount_namespace_refs.go
index 2c920ac41..63285fb8e 100644
--- a/pkg/sentry/vfs/mount_namespace_refs.go
+++ b/pkg/sentry/vfs/mount_namespace_refs.go
@@ -1,12 +1,12 @@
 package vfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/tcpip/link/tun/tun_endpoint_refs.go b/pkg/tcpip/link/tun/tun_endpoint_refs.go
index 06d11f0e1..e0595429c 100644
--- a/pkg/tcpip/link/tun/tun_endpoint_refs.go
+++ b/pkg/tcpip/link/tun/tun_endpoint_refs.go
@@ -1,12 +1,12 @@
 package tun
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so