diff --git a/container/autoetc.go b/container/autoetc.go
index 44b5d76..0334ad1 100644
--- a/container/autoetc.go
+++ b/container/autoetc.go
@@ -21,6 +21,7 @@ func (f *Ops) Etc(host *Absolute, prefix string) *Ops {
 
 type AutoEtcOp struct{ Prefix string }
 
+func (e *AutoEtcOp) Valid() bool             { return e != nil }
 func (e *AutoEtcOp) early(*setupState) error { return nil }
 func (e *AutoEtcOp) apply(state *setupState) error {
 	if state.nonrepeatable&nrAutoEtc != 0 {
@@ -66,7 +67,7 @@ func (e *AutoEtcOp) hostRel() string     { return ".host/" + e.Prefix }
 
 func (e *AutoEtcOp) Is(op Op) bool {
 	ve, ok := op.(*AutoEtcOp)
-	return ok && ((e == nil && ve == nil) || (e != nil && ve != nil && *e == *ve))
+	return ok && e.Valid() && ve.Valid() && *e == *ve
 }
 func (*AutoEtcOp) prefix() string   { return "setting up" }
 func (e *AutoEtcOp) String() string { return fmt.Sprintf("auto etc %s", e.Prefix) }
diff --git a/container/autoetc_test.go b/container/autoetc_test.go
index 4040fb0..efb4b3b 100644
--- a/container/autoetc_test.go
+++ b/container/autoetc_test.go
@@ -3,6 +3,12 @@ package container
 import "testing"
 
 func TestAutoEtcOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*AutoEtcOp)(nil), false},
+		{"zero", new(AutoEtcOp), true},
+		{"populated", &AutoEtcOp{Prefix: ":3"}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"pd", new(Ops).Etc(MustAbs("/etc/"), "048090b6ed8f9ebb10e275ff5d8c0659"), Ops{
 			&MkdirOp{Path: MustAbs("/etc/"), Perm: 0755},
diff --git a/container/autoroot.go b/container/autoroot.go
index a7a3f33..0de6bce 100644
--- a/container/autoroot.go
+++ b/container/autoroot.go
@@ -28,11 +28,9 @@ type AutoRootOp struct {
 	resolved []Op
 }
 
-func (r *AutoRootOp) early(state *setupState) error {
-	if r.Host == nil {
-		return syscall.EBADE
-	}
+func (r *AutoRootOp) Valid() bool { return r != nil && r.Host != nil }
 
+func (r *AutoRootOp) early(state *setupState) error {
 	if d, err := os.ReadDir(r.Host.String()); err != nil {
 		return wrapErrSelf(err)
 	} else {
@@ -72,9 +70,10 @@ func (r *AutoRootOp) apply(state *setupState) error {
 
 func (r *AutoRootOp) Is(op Op) bool {
 	vr, ok := op.(*AutoRootOp)
-	return ok && ((r == nil && vr == nil) || (r != nil && vr != nil &&
-		r.Host != nil && vr.Host != nil && r.Host.Is(vr.Host) &&
-		r.Prefix == vr.Prefix && r.Flags == vr.Flags))
+	return ok && r.Valid() && vr.Valid() &&
+		r.Host.Is(vr.Host) &&
+		r.Prefix == vr.Prefix &&
+		r.Flags == vr.Flags
 }
 func (*AutoRootOp) prefix() string { return "setting up" }
 func (r *AutoRootOp) String() string {
diff --git a/container/autoroot_test.go b/container/autoroot_test.go
index 5a77435..03df7c8 100644
--- a/container/autoroot_test.go
+++ b/container/autoroot_test.go
@@ -3,6 +3,12 @@ package container
 import "testing"
 
 func TestAutoRootOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*AutoRootOp)(nil), false},
+		{"zero", new(AutoRootOp), false},
+		{"valid", &AutoRootOp{Host: MustAbs("/")}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"pd", new(Ops).Root(MustAbs("/"), "048090b6ed8f9ebb10e275ff5d8c0659", BindWritable), Ops{
 			&AutoRootOp{
diff --git a/container/init.go b/container/init.go
index d516a3c..663bbc8 100644
--- a/container/init.go
+++ b/container/init.go
@@ -52,6 +52,7 @@ type (
 
 		prefix() string
 		Is(op Op) bool
+		Valid() bool
 		fmt.Stringer
 	}
 
@@ -167,8 +168,8 @@ func Init(prepare func(prefix string), setVerbose func(verbose bool)) {
 	via library functions after pivot_root, and implementations are expected to avoid changing
 	the state of the mount namespace */
 	for i, op := range *params.Ops {
-		if op == nil {
-			log.Fatalf("invalid op %d", i)
+		if op == nil || !op.Valid() {
+			log.Fatalf("invalid op at index %d", i)
 		}
 
 		if err := op.early(state); err != nil {
diff --git a/container/initbind.go b/container/initbind.go
index 0b34851..e19cb5d 100644
--- a/container/initbind.go
+++ b/container/initbind.go
@@ -24,6 +24,8 @@ type BindMountOp struct {
 	Flags int
 }
 
+func (b *BindMountOp) Valid() bool { return b != nil && b.Source != nil && b.Target != nil }
+
 const (
 	// BindOptional skips nonexistent host paths.
 	BindOptional = 1 << iota
@@ -34,10 +36,6 @@ const (
 )
 
 func (b *BindMountOp) early(*setupState) error {
-	if b.Source == nil || b.Target == nil {
-		return EBADE
-	}
-
 	if pathname, err := filepath.EvalSymlinks(b.Source.String()); err != nil {
 		if os.IsNotExist(err) && b.Flags&BindOptional != 0 {
 			// leave sourceFinal as nil
@@ -87,10 +85,10 @@ func (b *BindMountOp) apply(*setupState) error {
 
 func (b *BindMountOp) Is(op Op) bool {
 	vb, ok := op.(*BindMountOp)
-	return ok && ((b == nil && vb == nil) || (b != nil && vb != nil &&
-		b.Source != nil && vb.Source != nil && b.Source.Is(vb.Source) &&
-		b.Target != nil && vb.Target != nil && b.Target.Is(vb.Target) &&
-		b.Flags == vb.Flags))
+	return ok && b.Valid() && vb.Valid() &&
+		b.Source.Is(vb.Source) &&
+		b.Target.Is(vb.Target) &&
+		b.Flags == vb.Flags
 }
 func (*BindMountOp) prefix() string { return "mounting" }
 func (b *BindMountOp) String() string {
diff --git a/container/initbind_test.go b/container/initbind_test.go
index f079261..bae33f8 100644
--- a/container/initbind_test.go
+++ b/container/initbind_test.go
@@ -3,6 +3,14 @@ package container
 import "testing"
 
 func TestBindMountOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*BindMountOp)(nil), false},
+		{"zero", new(BindMountOp), false},
+		{"nil source", &BindMountOp{Target: MustAbs("/")}, false},
+		{"nil target", &BindMountOp{Source: MustAbs("/")}, false},
+		{"valid", &BindMountOp{Source: MustAbs("/"), Target: MustAbs("/")}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"autoetc", new(Ops).Bind(
 			MustAbs("/etc/"),
diff --git a/container/initdev.go b/container/initdev.go
index 71c30f4..48d70f3 100644
--- a/container/initdev.go
+++ b/container/initdev.go
@@ -33,11 +33,9 @@ type MountDevOp struct {
 	Write  bool
 }
 
+func (d *MountDevOp) Valid() bool             { return d != nil && d.Target != nil }
 func (d *MountDevOp) early(*setupState) error { return nil }
 func (d *MountDevOp) apply(state *setupState) error {
-	if d.Target == nil {
-		return EBADE
-	}
 	target := toSysroot(d.Target.String())
 
 	if err := mountTmpfs(SourceTmpfsDevtmpfs, target, MS_NOSUID|MS_NODEV, 0, state.ParentPerm); err != nil {
@@ -128,9 +126,10 @@ func (d *MountDevOp) apply(state *setupState) error {
 
 func (d *MountDevOp) Is(op Op) bool {
 	vd, ok := op.(*MountDevOp)
-	return ok && ((d == nil && vd == nil) || (d != nil && vd != nil &&
-		d.Target != nil && vd.Target != nil && d.Target.Is(vd.Target) &&
-		d.Mqueue == vd.Mqueue && d.Write == vd.Write))
+	return ok && d.Valid() && vd.Valid() &&
+		d.Target.Is(vd.Target) &&
+		d.Mqueue == vd.Mqueue &&
+		d.Write == vd.Write
 }
 func (*MountDevOp) prefix() string { return "mounting" }
 func (d *MountDevOp) String() string {
diff --git a/container/initdev_test.go b/container/initdev_test.go
index 0d6ea5a..4e23e6b 100644
--- a/container/initdev_test.go
+++ b/container/initdev_test.go
@@ -3,6 +3,12 @@ package container
 import "testing"
 
 func TestMountDevOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*MountDevOp)(nil), false},
+		{"zero", new(MountDevOp), false},
+		{"valid", &MountDevOp{Target: MustAbs("/dev/")}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"dev", new(Ops).Dev(MustAbs("/dev/"), true), Ops{
 			&MountDevOp{
diff --git a/container/initmkdir.go b/container/initmkdir.go
index 6153106..54aa4f7 100644
--- a/container/initmkdir.go
+++ b/container/initmkdir.go
@@ -4,7 +4,6 @@ import (
 	"encoding/gob"
 	"fmt"
 	"os"
-	"syscall"
 )
 
 func init() { gob.Register(new(MkdirOp)) }
@@ -21,19 +20,17 @@ type MkdirOp struct {
 	Perm os.FileMode
 }
 
+func (m *MkdirOp) Valid() bool             { return m != nil && m.Path != nil }
 func (m *MkdirOp) early(*setupState) error { return nil }
 func (m *MkdirOp) apply(*setupState) error {
-	if m.Path == nil {
-		return syscall.EBADE
-	}
 	return wrapErrSelf(os.MkdirAll(toSysroot(m.Path.String()), m.Perm))
 }
 
 func (m *MkdirOp) Is(op Op) bool {
 	vm, ok := op.(*MkdirOp)
-	return ok && ((m == nil && vm == nil) || (m != nil && vm != nil &&
-		m.Path != nil && vm.Path != nil && m.Path.Is(vm.Path) &&
-		m.Perm == vm.Perm))
+	return ok && m.Valid() && vm.Valid() &&
+		m.Path.Is(vm.Path) &&
+		m.Perm == vm.Perm
 }
 func (*MkdirOp) prefix() string   { return "creating" }
 func (m *MkdirOp) String() string { return fmt.Sprintf("directory %q perm %s", m.Path, m.Perm) }
diff --git a/container/initmkdir_test.go b/container/initmkdir_test.go
index d5c6f0b..ad32624 100644
--- a/container/initmkdir_test.go
+++ b/container/initmkdir_test.go
@@ -3,6 +3,12 @@ package container
 import "testing"
 
 func TestMkdirOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*MkdirOp)(nil), false},
+		{"zero", new(MkdirOp), false},
+		{"valid", &MkdirOp{Path: MustAbs("/.hakurei")}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"etc", new(Ops).Mkdir(MustAbs("/etc/"), 0), Ops{
 			&MkdirOp{Path: MustAbs("/etc/")},
diff --git a/container/initoverlay.go b/container/initoverlay.go
index 81b00b9..6822274 100644
--- a/container/initoverlay.go
+++ b/container/initoverlay.go
@@ -53,10 +53,10 @@ type MountOverlayOp struct {
 	lower []string
 	// The upperdir is normally on a writable filesystem.
 	//
-	// If Work is nil and Upper holds the special value [FHSRoot],
+	// If Work is nil and Upper holds the special value [AbsFHSRoot],
 	// an ephemeral upperdir and workdir will be set up.
 	//
-	// If both Work and Upper are empty strings, upperdir and workdir is omitted and the overlay is mounted readonly.
+	// If both Work and Upper are nil, upperdir and workdir is omitted and the overlay is mounted readonly.
 	Upper *Absolute
 	// formatted for [OptionOverlayUpperdir], resolved, prefixed and escaped during early
 	upper string
@@ -68,6 +68,19 @@ type MountOverlayOp struct {
 	ephemeral bool
 }
 
+func (o *MountOverlayOp) Valid() bool {
+	if o == nil {
+		return false
+	}
+	if o.Work != nil && o.Upper == nil {
+		return false
+	}
+	if slices.Contains(o.Lower, nil) {
+		return false
+	}
+	return o.Target != nil
+}
+
 func (o *MountOverlayOp) early(*setupState) error {
 	if o.Work == nil && o.Upper != nil {
 		switch o.Upper.String() {
@@ -104,11 +117,7 @@ func (o *MountOverlayOp) early(*setupState) error {
 	}
 
 	o.lower = make([]string, len(o.Lower))
-	for i, a := range o.Lower {
-		if a == nil {
-			return EBADE
-		}
-
+	for i, a := range o.Lower { // nil checked in Valid
 		if v, err := filepath.EvalSymlinks(a.String()); err != nil {
 			return wrapErrSelf(err)
 		} else {
@@ -119,9 +128,6 @@ func (o *MountOverlayOp) early(*setupState) error {
 }
 
 func (o *MountOverlayOp) apply(state *setupState) error {
-	if o.Target == nil {
-		return EBADE
-	}
 	target := toSysroot(o.Target.String())
 	if err := os.MkdirAll(target, state.ParentPerm); err != nil {
 		return wrapErrSelf(err)
@@ -163,10 +169,10 @@ func (o *MountOverlayOp) apply(state *setupState) error {
 
 func (o *MountOverlayOp) Is(op Op) bool {
 	vo, ok := op.(*MountOverlayOp)
-	return ok && ((o == nil && vo == nil) || (o != nil && vo != nil &&
-		o.Target != nil && vo.Target != nil && o.Target.Is(vo.Target) &&
+	return ok && o.Valid() && vo.Valid() &&
+		o.Target.Is(vo.Target) &&
 		slices.EqualFunc(o.Lower, vo.Lower, func(a *Absolute, v *Absolute) bool { return a.Is(v) }) &&
-		o.Upper.Is(vo.Upper) && o.Work.Is(vo.Work)))
+		o.Upper.Is(vo.Upper) && o.Work.Is(vo.Work)
 }
 func (*MountOverlayOp) prefix() string { return "mounting" }
 func (o *MountOverlayOp) String() string {
diff --git a/container/initoverlay_test.go b/container/initoverlay_test.go
index ae4cd1b..68377dd 100644
--- a/container/initoverlay_test.go
+++ b/container/initoverlay_test.go
@@ -3,6 +3,15 @@ package container
 import "testing"
 
 func TestMountOverlayOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*MountOverlayOp)(nil), false},
+		{"zero", new(MountOverlayOp), false},
+		{"nil lower", &MountOverlayOp{Target: MustAbs("/"), Lower: []*Absolute{nil}}, false},
+		{"ro", &MountOverlayOp{Target: MustAbs("/"), Lower: []*Absolute{MustAbs("/")}}, true},
+		{"ro work", &MountOverlayOp{Target: MustAbs("/"), Work: MustAbs("/tmp/")}, false},
+		{"rw", &MountOverlayOp{Target: MustAbs("/"), Lower: []*Absolute{MustAbs("/")}, Upper: MustAbs("/"), Work: MustAbs("/")}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"full", new(Ops).Overlay(
 			MustAbs("/nix/store"),
diff --git a/container/initplace.go b/container/initplace.go
index 9114694..2d98d94 100644
--- a/container/initplace.go
+++ b/container/initplace.go
@@ -35,12 +35,9 @@ type TmpfileOp struct {
 	Data []byte
 }
 
+func (t *TmpfileOp) Valid() bool             { return t != nil && t.Path != nil }
 func (t *TmpfileOp) early(*setupState) error { return nil }
 func (t *TmpfileOp) apply(state *setupState) error {
-	if t.Path == nil {
-		return EBADE
-	}
-
 	var tmpPath string
 	if f, err := os.CreateTemp(FHSRoot, intermediatePatternTmpfile); err != nil {
 		return wrapErrSelf(err)
@@ -72,7 +69,8 @@ func (t *TmpfileOp) apply(state *setupState) error {
 
 func (t *TmpfileOp) Is(op Op) bool {
 	vt, ok := op.(*TmpfileOp)
-	return ok && t.Path != nil && vt.Path != nil && t.Path.Is(vt.Path) &&
+	return ok && t.Valid() && vt.Valid() &&
+		t.Path.Is(vt.Path) &&
 		string(t.Data) == string(vt.Data)
 }
 func (*TmpfileOp) prefix() string { return "placing" }
diff --git a/container/initplace_test.go b/container/initplace_test.go
index e1d8163..db3d955 100644
--- a/container/initplace_test.go
+++ b/container/initplace_test.go
@@ -3,6 +3,12 @@ package container
 import "testing"
 
 func TestTmpfileOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*TmpfileOp)(nil), false},
+		{"zero", new(TmpfileOp), false},
+		{"valid", &TmpfileOp{Path: MustAbs("/etc/passwd")}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"noref", new(Ops).Place(MustAbs("/etc/passwd"), []byte(`chronos:x:65534:65534:Hakurei:/var/empty:/bin/zsh`)), Ops{
 			&TmpfileOp{
diff --git a/container/initproc.go b/container/initproc.go
index d3c3753..9b9769c 100644
--- a/container/initproc.go
+++ b/container/initproc.go
@@ -16,15 +16,11 @@ func (f *Ops) Proc(target *Absolute) *Ops {
 }
 
 // MountProcOp mounts a new instance of [FstypeProc] on container path Target.
-type MountProcOp struct {
-	Target *Absolute
-}
+type MountProcOp struct{ Target *Absolute }
 
+func (p *MountProcOp) Valid() bool             { return p != nil && p.Target != nil }
 func (p *MountProcOp) early(*setupState) error { return nil }
 func (p *MountProcOp) apply(state *setupState) error {
-	if p.Target == nil {
-		return EBADE
-	}
 	target := toSysroot(p.Target.String())
 	if err := os.MkdirAll(target, state.ParentPerm); err != nil {
 		return wrapErrSelf(err)
@@ -35,8 +31,8 @@ func (p *MountProcOp) apply(state *setupState) error {
 
 func (p *MountProcOp) Is(op Op) bool {
 	vp, ok := op.(*MountProcOp)
-	return ok && ((p == nil && vp == nil) ||
-		(p.Target != nil && vp.Target != nil && p.Target.Is(vp.Target)))
+	return ok && p.Valid() && vp.Valid() &&
+		p.Target.Is(vp.Target)
 }
 func (*MountProcOp) prefix() string   { return "mounting" }
 func (p *MountProcOp) String() string { return fmt.Sprintf("proc on %q", p.Target) }
diff --git a/container/initproc_test.go b/container/initproc_test.go
index fe37732..eb55e4e 100644
--- a/container/initproc_test.go
+++ b/container/initproc_test.go
@@ -3,6 +3,12 @@ package container
 import "testing"
 
 func TestMountProcOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*MountProcOp)(nil), false},
+		{"zero", new(MountProcOp), false},
+		{"valid", &MountProcOp{Target: MustAbs("/proc/")}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"proc", new(Ops).Proc(MustAbs("/proc/")), Ops{
 			&MountProcOp{Target: MustAbs("/proc/")},
diff --git a/container/initremount.go b/container/initremount.go
index 77efc21..74bea09 100644
--- a/container/initremount.go
+++ b/container/initremount.go
@@ -3,7 +3,6 @@ package container
 import (
 	"encoding/gob"
 	"fmt"
-	"syscall"
 )
 
 func init() { gob.Register(new(RemountOp)) }
@@ -20,20 +19,18 @@ type RemountOp struct {
 	Flags  uintptr
 }
 
+func (r *RemountOp) Valid() bool           { return r != nil && r.Target != nil }
 func (*RemountOp) early(*setupState) error { return nil }
 func (r *RemountOp) apply(*setupState) error {
-	if r.Target == nil {
-		return syscall.EBADE
-	}
 	return wrapErrSuffix(hostProc.remount(toSysroot(r.Target.String()), r.Flags),
 		fmt.Sprintf("cannot remount %q:", r.Target))
 }
 
 func (r *RemountOp) Is(op Op) bool {
 	vr, ok := op.(*RemountOp)
-	return ok && ((r == nil && vr == nil) ||
-		(r.Target != nil && vr.Target != nil && r.Target.Is(vr.Target)) &&
-			r.Flags == vr.Flags)
+	return ok && r.Valid() && vr.Valid() &&
+		r.Target.Is(vr.Target) &&
+		r.Flags == vr.Flags
 }
 func (*RemountOp) prefix() string   { return "remounting" }
 func (r *RemountOp) String() string { return fmt.Sprintf("%q flags %#x", r.Target, r.Flags) }
diff --git a/container/initremount_test.go b/container/initremount_test.go
index a59160b..db5476e 100644
--- a/container/initremount_test.go
+++ b/container/initremount_test.go
@@ -6,6 +6,12 @@ import (
 )
 
 func TestRemountOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*RemountOp)(nil), false},
+		{"zero", new(RemountOp), false},
+		{"valid", &RemountOp{Target: MustAbs("/"), Flags: syscall.MS_RDONLY}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"root", new(Ops).Remount(MustAbs("/"), syscall.MS_RDONLY), Ops{
 			&RemountOp{
diff --git a/container/initsymlink.go b/container/initsymlink.go
index 3580554..3060817 100644
--- a/container/initsymlink.go
+++ b/container/initsymlink.go
@@ -26,6 +26,8 @@ type SymlinkOp struct {
 	Dereference bool
 }
 
+func (l *SymlinkOp) Valid() bool { return l != nil && l.Target != nil && l.LinkName != zeroString }
+
 func (l *SymlinkOp) early(*setupState) error {
 	if l.Dereference {
 		if !isAbs(l.LinkName) {
@@ -41,9 +43,6 @@ func (l *SymlinkOp) early(*setupState) error {
 }
 
 func (l *SymlinkOp) apply(state *setupState) error {
-	if l.Target == nil {
-		return syscall.EBADE
-	}
 	target := toSysroot(l.Target.String())
 	if err := os.MkdirAll(path.Dir(target), state.ParentPerm); err != nil {
 		return wrapErrSelf(err)
@@ -56,9 +55,10 @@ func (l *SymlinkOp) apply(state *setupState) error {
 
 func (l *SymlinkOp) Is(op Op) bool {
 	vl, ok := op.(*SymlinkOp)
-	return ok && ((l == nil && vl == nil) ||
-		(l.Target != nil && vl.Target != nil && l.Target.Is(vl.Target)) &&
-			l.LinkName == vl.LinkName && l.Dereference == vl.Dereference)
+	return ok && l.Valid() && vl.Valid() &&
+		l.Target.Is(vl.Target) &&
+		l.LinkName == vl.LinkName &&
+		l.Dereference == vl.Dereference
 }
 func (*SymlinkOp) prefix() string { return "creating" }
 func (l *SymlinkOp) String() string {
diff --git a/container/initsymlink_test.go b/container/initsymlink_test.go
index 1051beb..4ae2da8 100644
--- a/container/initsymlink_test.go
+++ b/container/initsymlink_test.go
@@ -3,6 +3,14 @@ package container
 import "testing"
 
 func TestSymlinkOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*SymlinkOp)(nil), false},
+		{"zero", new(SymlinkOp), false},
+		{"nil target", &SymlinkOp{LinkName: "/run/current-system"}, false},
+		{"zero linkname", &SymlinkOp{Target: MustAbs("/run/current-system")}, false},
+		{"valid", &SymlinkOp{Target: MustAbs("/run/current-system"), LinkName: "/run/current-system", Dereference: true}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"current-system", new(Ops).Link(
 			MustAbs("/run/current-system"),
diff --git a/container/inittmpfs.go b/container/inittmpfs.go
index 332fec8..d313a11 100644
--- a/container/inittmpfs.go
+++ b/container/inittmpfs.go
@@ -31,11 +31,9 @@ type MountTmpfsOp struct {
 	Perm   os.FileMode
 }
 
+func (t *MountTmpfsOp) Valid() bool             { return t != nil && t.Path != nil && t.FSName != zeroString }
 func (t *MountTmpfsOp) early(*setupState) error { return nil }
 func (t *MountTmpfsOp) apply(*setupState) error {
-	if t.Path == nil {
-		return EBADE
-	}
 	if t.Size < 0 || t.Size > math.MaxUint>>1 {
 		return msg.WrapErr(EBADE, fmt.Sprintf("size %d out of bounds", t.Size))
 	}
@@ -44,9 +42,12 @@ func (t *MountTmpfsOp) apply(*setupState) error {
 
 func (t *MountTmpfsOp) Is(op Op) bool {
 	vt, ok := op.(*MountTmpfsOp)
-	return ok && ((t == nil && vt == nil) ||
-		(t.Path != nil && vt.Path != nil && t.Path.Is(vt.Path)) &&
-			t.FSName == vt.FSName && t.Flags == vt.Flags && t.Size == vt.Size && t.Perm == vt.Perm)
+	return ok && t.Valid() && vt.Valid() &&
+		t.FSName == vt.FSName &&
+		t.Path.Is(vt.Path) &&
+		t.Flags == vt.Flags &&
+		t.Size == vt.Size &&
+		t.Perm == vt.Perm
 }
 func (*MountTmpfsOp) prefix() string   { return "mounting" }
 func (t *MountTmpfsOp) String() string { return fmt.Sprintf("tmpfs on %q size %d", t.Path, t.Size) }
diff --git a/container/inittmpfs_test.go b/container/inittmpfs_test.go
index c36820c..c924586 100644
--- a/container/inittmpfs_test.go
+++ b/container/inittmpfs_test.go
@@ -6,6 +6,14 @@ import (
 )
 
 func TestMountTmpfsOp(t *testing.T) {
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*MountTmpfsOp)(nil), false},
+		{"zero", new(MountTmpfsOp), false},
+		{"nil path", &MountTmpfsOp{FSName: "tmpfs"}, false},
+		{"zero fsname", &MountTmpfsOp{Path: MustAbs("/tmp/")}, false},
+		{"valid", &MountTmpfsOp{FSName: "tmpfs", Path: MustAbs("/tmp/")}, true},
+	})
+
 	checkOpsBuilder(t, []opsBuilderTestCase{
 		{"runtime", new(Ops).Tmpfs(
 			MustAbs("/run/user"),
diff --git a/container/mount_test.go b/container/mount_test.go
index 4c598b3..64cac28 100644
--- a/container/mount_test.go
+++ b/container/mount_test.go
@@ -49,6 +49,24 @@ func TestEscapeOverlayDataSegment(t *testing.T) {
 	}
 }
 
+type opValidTestCase struct {
+	name string
+	op   Op
+	want bool
+}
+
+func checkOpsValid(t *testing.T, testCases []opValidTestCase) {
+	t.Run("valid", func(t *testing.T) {
+		for _, tc := range testCases {
+			t.Run(tc.name, func(t *testing.T) {
+				if got := tc.op.Valid(); got != tc.want {
+					t.Errorf("Valid: %v, want %v", got, tc.want)
+				}
+			})
+		}
+	})
+}
+
 type opsBuilderTestCase struct {
 	name string
 	ops  *Ops