Rename marshal.Task to marshal.CopyContext.

CopyContext is a better name for the interface because from
go-marshal's perspective, the interface has nothing to do with a
task. A kernel.Task happens to implement the interface, but so can
other things like MemoryManager and IO sequences.

PiperOrigin-RevId: 331959678

13 files changed, 180 insertions, 178 deletions

diff --git a/pkg/abi/linux/netfilter.go b/pkg/abi/linux/netfilter.go
index 6ef91b402..1c5b34711 100644
--- a/pkg/abi/linux/netfilter.go
+++ b/pkg/abi/linux/netfilter.go
@@ -450,9 +450,9 @@ func (ke *KernelIPTGetEntries) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
-func (ke *KernelIPTGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-	buf := task.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay.
-	length, err := task.CopyInBytes(addr, buf)    // escapes: okay.
+func (ke *KernelIPTGetEntries) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+	buf := cc.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay.
+	length, err := cc.CopyInBytes(addr, buf)    // escapes: okay.
 	// Unmarshal unconditionally. If we had a short copy-in, this results in a
 	// partially unmarshalled struct.
 	ke.UnmarshalBytes(buf) // escapes: fallback.
@@ -460,21 +460,21 @@ func (ke *KernelIPTGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (int
 }
 
 // CopyOut implements marshal.Marshallable.CopyOut.
-func (ke *KernelIPTGetEntries) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
+func (ke *KernelIPTGetEntries) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
 	// Type KernelIPTGetEntries doesn't have a packed layout in memory, fall
 	// back to MarshalBytes.
-	return task.CopyOutBytes(addr, ke.marshalAll(task))
+	return cc.CopyOutBytes(addr, ke.marshalAll(cc))
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
-func (ke *KernelIPTGetEntries) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
+func (ke *KernelIPTGetEntries) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
 	// Type KernelIPTGetEntries doesn't have a packed layout in memory, fall
 	// back to MarshalBytes.
-	return task.CopyOutBytes(addr, ke.marshalAll(task)[:limit])
+	return cc.CopyOutBytes(addr, ke.marshalAll(cc)[:limit])
 }
 
-func (ke *KernelIPTGetEntries) marshalAll(task marshal.Task) []byte {
-	buf := task.CopyScratchBuffer(ke.SizeBytes())
+func (ke *KernelIPTGetEntries) marshalAll(cc marshal.CopyContext) []byte {
+	buf := cc.CopyScratchBuffer(ke.SizeBytes())
 	ke.MarshalBytes(buf)
 	return buf
 }
diff --git a/pkg/abi/linux/netfilter_ipv6.go b/pkg/abi/linux/netfilter_ipv6.go
index 347c8c591..a137940b6 100644
--- a/pkg/abi/linux/netfilter_ipv6.go
+++ b/pkg/abi/linux/netfilter_ipv6.go
@@ -128,9 +128,9 @@ func (ke *KernelIP6TGetEntries) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
-func (ke *KernelIP6TGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-	buf := task.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay.
-	length, err := task.CopyInBytes(addr, buf)    // escapes: okay.
+func (ke *KernelIP6TGetEntries) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+	buf := cc.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay.
+	length, err := cc.CopyInBytes(addr, buf)    // escapes: okay.
 	// Unmarshal unconditionally. If we had a short copy-in, this results
 	// in a partially unmarshalled struct.
 	ke.UnmarshalBytes(buf) // escapes: fallback.
@@ -138,21 +138,21 @@ func (ke *KernelIP6TGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (in
 }
 
 // CopyOut implements marshal.Marshallable.CopyOut.
-func (ke *KernelIP6TGetEntries) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
+func (ke *KernelIP6TGetEntries) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
 	// Type KernelIP6TGetEntries doesn't have a packed layout in memory,
 	// fall back to MarshalBytes.
-	return task.CopyOutBytes(addr, ke.marshalAll(task))
+	return cc.CopyOutBytes(addr, ke.marshalAll(cc))
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
-func (ke *KernelIP6TGetEntries) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
+func (ke *KernelIP6TGetEntries) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
 	// Type KernelIP6TGetEntries doesn't have a packed layout in memory, fall
 	// back to MarshalBytes.
-	return task.CopyOutBytes(addr, ke.marshalAll(task)[:limit])
+	return cc.CopyOutBytes(addr, ke.marshalAll(cc)[:limit])
 }
 
-func (ke *KernelIP6TGetEntries) marshalAll(task marshal.Task) []byte {
-	buf := task.CopyScratchBuffer(ke.SizeBytes())
+func (ke *KernelIP6TGetEntries) marshalAll(cc marshal.CopyContext) []byte {
+	buf := cc.CopyScratchBuffer(ke.SizeBytes())
 	ke.MarshalBytes(buf)
 	return buf
 }
diff --git a/pkg/marshal/marshal.go b/pkg/marshal/marshal.go
index 85b196f08..d8cb44b40 100644
--- a/pkg/marshal/marshal.go
+++ b/pkg/marshal/marshal.go
@@ -26,9 +26,10 @@ import (
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
-// Task provides a subset of kernel.Task, used in marshalling. We don't import
-// the kernel package directly to avoid circular dependency.
-type Task interface {
+// CopyContext defines the memory operations required to marshal to and from
+// user memory. Typically, kernel.Task is used to provide implementations for
+// these operations.
+type CopyContext interface {
 	// CopyScratchBuffer provides a task goroutine-local scratch buffer. See
 	// kernel.CopyScratchBuffer.
 	CopyScratchBuffer(size int) []byte
@@ -107,7 +108,7 @@ type Marshallable interface {
 	// If the copy-in from the task memory is only partially successful, CopyIn
 	// should still attempt to deserialize as much data as possible. See comment
 	// for UnmarshalBytes.
-	CopyIn(task Task, addr usermem.Addr) (int, error)
+	CopyIn(cc CopyContext, addr usermem.Addr) (int, error)
 
 	// CopyOut serializes a Marshallable type to a task's memory. This may only
 	// be called from a task goroutine. This is more efficient than calling
@@ -118,7 +119,7 @@ type Marshallable interface {
 	// The copy-out to the task memory may be partially successful, in which
 	// case CopyOut returns how much data was serialized. See comment for
 	// MarshalBytes for implications.
-	CopyOut(task Task, addr usermem.Addr) (int, error)
+	CopyOut(cc CopyContext, addr usermem.Addr) (int, error)
 
 	// CopyOutN is like CopyOut, but explicitly requests a partial
 	// copy-out. Note that this may yield unexpected results for non-packed
@@ -126,7 +127,7 @@ type Marshallable interface {
 	// comment on MarshalBytes.
 	//
 	// The limit must be less than or equal to SizeBytes().
-	CopyOutN(task Task, addr usermem.Addr, limit int) (int, error)
+	CopyOutN(cc CopyContext, addr usermem.Addr, limit int) (int, error)
 }
 
 // go-marshal generates additional functions for a type based on additional
@@ -156,10 +157,10 @@ type Marshallable interface {
 // func UnmarshalUnsafeFooSlice(dst []Foo, src []byte) (int, error) { ... }
 //
 // // CopyFooSliceIn copies in a slice of Foo objects from the task's memory.
-// func CopyFooSliceIn(task marshal.Task, addr usermem.Addr, dst []Foo) (int, error) { ... }
+// func CopyFooSliceIn(cc marshal.CopyContext, addr usermem.Addr, dst []Foo) (int, error) { ... }
 //
 // // CopyFooSliceIn copies out a slice of Foo objects to the task's memory.
-// func CopyFooSliceOut(task marshal.Task, addr usermem.Addr, src []Foo) (int, error) { ... }
+// func CopyFooSliceOut(cc marshal.CopyContext, addr usermem.Addr, src []Foo) (int, error) { ... }
 //
 // The name of the functions are of the format "Copy%sIn" and "Copy%sOut", where
 // %s is the first argument to the slice clause. This directive is not supported
@@ -174,10 +175,10 @@ type Marshallable interface {
 // This is only valid on newtypes on primitives, and causes the generated
 // functions to accept slices of the inner type instead:
 //
-// func CopyInt32SliceIn(task marshal.Task, addr usermem.Addr, dst []int32) (int, error) { ... }
+// func CopyInt32SliceIn(cc marshal.CopyContext, addr usermem.Addr, dst []int32) (int, error) { ... }
 //
 // Without "inner", they would instead be:
 //
-// func CopyInt32SliceIn(task marshal.Task, addr usermem.Addr, dst []Int32) (int, error) { ... }
+// func CopyInt32SliceIn(cc marshal.CopyContext, addr usermem.Addr, dst []Int32) (int, error) { ... }
 //
 // This may help avoid a cast depending on how the generated functions are used.
diff --git a/pkg/marshal/marshal_impl_util.go b/pkg/marshal/marshal_impl_util.go
index 89c7d3575..69f33321e 100644
--- a/pkg/marshal/marshal_impl_util.go
+++ b/pkg/marshal/marshal_impl_util.go
@@ -63,16 +63,16 @@ func (StubMarshallable) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyIn implements Marshallable.CopyIn.
-func (StubMarshallable) CopyIn(task Task, addr usermem.Addr) (int, error) {
+func (StubMarshallable) CopyIn(cc CopyContext, addr usermem.Addr) (int, error) {
 	panic("Please implement your own CopyIn function")
 }
 
 // CopyOut implements Marshallable.CopyOut.
-func (StubMarshallable) CopyOut(task Task, addr usermem.Addr) (int, error) {
+func (StubMarshallable) CopyOut(cc CopyContext, addr usermem.Addr) (int, error) {
 	panic("Please implement your own CopyOut function")
 }
 
 // CopyOutN implements Marshallable.CopyOutN.
-func (StubMarshallable) CopyOutN(task Task, addr usermem.Addr, limit int) (int, error) {
+func (StubMarshallable) CopyOutN(cc CopyContext, addr usermem.Addr, limit int) (int, error) {
 	panic("Please implement your own CopyOutN function")
 }
diff --git a/pkg/marshal/primitive/primitive.go b/pkg/marshal/primitive/primitive.go
index 140a9b78c..dfdae5d60 100644
--- a/pkg/marshal/primitive/primitive.go
+++ b/pkg/marshal/primitive/primitive.go
@@ -101,18 +101,18 @@ func (b *ByteSlice) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
-func (b *ByteSlice) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-	return task.CopyInBytes(addr, *b)
+func (b *ByteSlice) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+	return cc.CopyInBytes(addr, *b)
 }
 
 // CopyOut implements marshal.Marshallable.CopyOut.
-func (b *ByteSlice) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
-	return task.CopyOutBytes(addr, *b)
+func (b *ByteSlice) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+	return cc.CopyOutBytes(addr, *b)
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
-func (b *ByteSlice) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-	return task.CopyOutBytes(addr, (*b)[:limit])
+func (b *ByteSlice) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
+	return cc.CopyOutBytes(addr, (*b)[:limit])
 }
 
 // WriteTo implements io.WriterTo.WriteTo.
@@ -130,9 +130,9 @@ var _ marshal.Marshallable = (*ByteSlice)(nil)
 
 // CopyInt16In is a convenient wrapper for copying in an int16 from the task's
 // memory.
-func CopyInt16In(task marshal.Task, addr usermem.Addr, dst *int16) (int, error) {
+func CopyInt16In(cc marshal.CopyContext, addr usermem.Addr, dst *int16) (int, error) {
 	var buf Int16
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -142,16 +142,16 @@ func CopyInt16In(task marshal.Task, addr usermem.Addr, dst *int16) (int, error)
 
 // CopyInt16Out is a convenient wrapper for copying out an int16 to the task's
 // memory.
-func CopyInt16Out(task marshal.Task, addr usermem.Addr, src int16) (int, error) {
+func CopyInt16Out(cc marshal.CopyContext, addr usermem.Addr, src int16) (int, error) {
 	srcP := Int16(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // CopyUint16In is a convenient wrapper for copying in a uint16 from the task's
 // memory.
-func CopyUint16In(task marshal.Task, addr usermem.Addr, dst *uint16) (int, error) {
+func CopyUint16In(cc marshal.CopyContext, addr usermem.Addr, dst *uint16) (int, error) {
 	var buf Uint16
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -161,18 +161,18 @@ func CopyUint16In(task marshal.Task, addr usermem.Addr, dst *uint16) (int, error
 
 // CopyUint16Out is a convenient wrapper for copying out a uint16 to the task's
 // memory.
-func CopyUint16Out(task marshal.Task, addr usermem.Addr, src uint16) (int, error) {
+func CopyUint16Out(cc marshal.CopyContext, addr usermem.Addr, src uint16) (int, error) {
 	srcP := Uint16(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // 32-bit integers
 
 // CopyInt32In is a convenient wrapper for copying in an int32 from the task's
 // memory.
-func CopyInt32In(task marshal.Task, addr usermem.Addr, dst *int32) (int, error) {
+func CopyInt32In(cc marshal.CopyContext, addr usermem.Addr, dst *int32) (int, error) {
 	var buf Int32
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -182,16 +182,16 @@ func CopyInt32In(task marshal.Task, addr usermem.Addr, dst *int32) (int, error)
 
 // CopyInt32Out is a convenient wrapper for copying out an int32 to the task's
 // memory.
-func CopyInt32Out(task marshal.Task, addr usermem.Addr, src int32) (int, error) {
+func CopyInt32Out(cc marshal.CopyContext, addr usermem.Addr, src int32) (int, error) {
 	srcP := Int32(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // CopyUint32In is a convenient wrapper for copying in a uint32 from the task's
 // memory.
-func CopyUint32In(task marshal.Task, addr usermem.Addr, dst *uint32) (int, error) {
+func CopyUint32In(cc marshal.CopyContext, addr usermem.Addr, dst *uint32) (int, error) {
 	var buf Uint32
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -201,18 +201,18 @@ func CopyUint32In(task marshal.Task, addr usermem.Addr, dst *uint32) (int, error
 
 // CopyUint32Out is a convenient wrapper for copying out a uint32 to the task's
 // memory.
-func CopyUint32Out(task marshal.Task, addr usermem.Addr, src uint32) (int, error) {
+func CopyUint32Out(cc marshal.CopyContext, addr usermem.Addr, src uint32) (int, error) {
 	srcP := Uint32(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // 64-bit integers
 
 // CopyInt64In is a convenient wrapper for copying in an int64 from the task's
 // memory.
-func CopyInt64In(task marshal.Task, addr usermem.Addr, dst *int64) (int, error) {
+func CopyInt64In(cc marshal.CopyContext, addr usermem.Addr, dst *int64) (int, error) {
 	var buf Int64
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -222,16 +222,16 @@ func CopyInt64In(task marshal.Task, addr usermem.Addr, dst *int64) (int, error)
 
 // CopyInt64Out is a convenient wrapper for copying out an int64 to the task's
 // memory.
-func CopyInt64Out(task marshal.Task, addr usermem.Addr, src int64) (int, error) {
+func CopyInt64Out(cc marshal.CopyContext, addr usermem.Addr, src int64) (int, error) {
 	srcP := Int64(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // CopyUint64In is a convenient wrapper for copying in a uint64 from the task's
 // memory.
-func CopyUint64In(task marshal.Task, addr usermem.Addr, dst *uint64) (int, error) {
+func CopyUint64In(cc marshal.CopyContext, addr usermem.Addr, dst *uint64) (int, error) {
 	var buf Uint64
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -241,7 +241,7 @@ func CopyUint64In(task marshal.Task, addr usermem.Addr, dst *uint64) (int, error
 
 // CopyUint64Out is a convenient wrapper for copying out a uint64 to the task's
 // memory.
-func CopyUint64Out(task marshal.Task, addr usermem.Addr, src uint64) (int, error) {
+func CopyUint64Out(cc marshal.CopyContext, addr usermem.Addr, src uint64) (int, error) {
 	srcP := Uint64(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
diff --git a/pkg/sentry/fsimpl/fuse/dev_test.go b/pkg/sentry/fsimpl/fuse/dev_test.go
index 6baf56520..c18921dd8 100644
--- a/pkg/sentry/fsimpl/fuse/dev_test.go
+++ b/pkg/sentry/fsimpl/fuse/dev_test.go
@@ -408,17 +408,17 @@ func (t *testPayload) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
-func (t *testPayload) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
+func (t *testPayload) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
 	panic("not implemented")
 }
 
 // CopyOut implements marshal.Marshallable.CopyOut.
-func (t *testPayload) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
+func (t *testPayload) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
 	panic("not implemented")
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
-func (t *testPayload) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
+func (t *testPayload) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
 	panic("not implemented")
 }
 
diff --git a/pkg/sentry/kernel/task_usermem.go b/pkg/sentry/kernel/task_usermem.go
index 14d765af1..ce134bf54 100644
--- a/pkg/sentry/kernel/task_usermem.go
+++ b/pkg/sentry/kernel/task_usermem.go
@@ -18,6 +18,7 @@ import (
 	"math"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/marshal"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
 )
@@ -280,29 +281,29 @@ func (t *Task) IovecsIOSequence(addr usermem.Addr, iovcnt int, opts usermem.IOOp
 	}, nil
 }
 
-// CopyContext wraps a task to allow copying memory to and from the
-// task memory with user specified usermem.IOOpts.
-type CopyContext struct {
+// copyContext implements marshal.CopyContext. It wraps a task to allow copying
+// memory to and from the task memory with custom usermem.IOOpts.
+type copyContext struct {
 	*Task
 	opts usermem.IOOpts
 }
 
 // AsCopyContext wraps the task and returns it as CopyContext.
-func (t *Task) AsCopyContext(opts usermem.IOOpts) *CopyContext {
-	return &CopyContext{t, opts}
+func (t *Task) AsCopyContext(opts usermem.IOOpts) marshal.CopyContext {
+	return &copyContext{t, opts}
 }
 
 // CopyInString copies a string in from the task's memory.
-func (t *CopyContext) CopyInString(addr usermem.Addr, maxLen int) (string, error) {
+func (t *copyContext) CopyInString(addr usermem.Addr, maxLen int) (string, error) {
 	return usermem.CopyStringIn(t, t.MemoryManager(), addr, maxLen, t.opts)
 }
 
 // CopyInBytes copies task memory into dst from an IO context.
-func (t *CopyContext) CopyInBytes(addr usermem.Addr, dst []byte) (int, error) {
+func (t *copyContext) CopyInBytes(addr usermem.Addr, dst []byte) (int, error) {
 	return t.MemoryManager().CopyIn(t, addr, dst, t.opts)
 }
 
 // CopyOutBytes copies src into task memoryfrom an IO context.
-func (t *CopyContext) CopyOutBytes(addr usermem.Addr, src []byte) (int, error) {
+func (t *copyContext) CopyOutBytes(addr usermem.Addr, src []byte) (int, error) {
 	return t.MemoryManager().CopyOut(t, addr, src, t.opts)
 }
diff --git a/tools/go_marshal/gomarshal/generator.go b/tools/go_marshal/gomarshal/generator.go
index fd7cce8fa..72ed6d109 100644
--- a/tools/go_marshal/gomarshal/generator.go
+++ b/tools/go_marshal/gomarshal/generator.go
@@ -38,8 +38,8 @@ import (
 // All recievers are single letters, so we don't allow import aliases to be a
 // single letter.
 var badIdents = []string{
-	"addr", "blk", "buf", "dst", "dsts", "count", "err", "hdr", "idx", "inner",
-	"length", "limit", "ptr", "size", "src", "srcs", "task", "val",
+	"addr", "blk", "buf", "cc", "dst", "dsts", "count", "err", "hdr", "idx",
+	"inner", "length", "limit", "ptr", "size", "src", "srcs", "val",
 	// All single-letter identifiers.
 }
 
diff --git a/tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go b/tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go
index 72ef03a22..7525b52da 100644
--- a/tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go
+++ b/tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go
@@ -102,11 +102,11 @@ func (g *interfaceGenerator) emitMarshallableForArrayNewtype(n *ast.Ident, a *as
 
 	g.emit("// CopyOutN implements marshal.Marshallable.CopyOutN.\n")
 	g.emit("//go:nosplit\n")
-	g.emit("func (%s *%s) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
 		g.emitCastToByteSlice(g.r, "buf", fmt.Sprintf("%s.SizeBytes()", g.r))
 
-		g.emit("length, err := task.CopyOutBytes(addr, buf[:limit]) // escapes: okay.\n")
+		g.emit("length, err := cc.CopyOutBytes(addr, buf[:limit]) // escapes: okay.\n")
 		g.emitKeepAlive(g.r)
 		g.emit("return length, err\n")
 	})
@@ -114,19 +114,19 @@ func (g *interfaceGenerator) emitMarshallableForArrayNewtype(n *ast.Ident, a *as
 
 	g.emit("// CopyOut implements marshal.Marshallable.CopyOut.\n")
 	g.emit("//go:nosplit\n")
-	g.emit("func (%s *%s) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
-		g.emit("return %s.CopyOutN(task, addr, %s.SizeBytes())\n", g.r, g.r)
+		g.emit("return %s.CopyOutN(cc, addr, %s.SizeBytes())\n", g.r, g.r)
 	})
 	g.emit("}\n\n")
 
 	g.emit("// CopyIn implements marshal.Marshallable.CopyIn.\n")
 	g.emit("//go:nosplit\n")
-	g.emit("func (%s *%s) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
 		g.emitCastToByteSlice(g.r, "buf", fmt.Sprintf("%s.SizeBytes()", g.r))
 
-		g.emit("length, err := task.CopyInBytes(addr, buf) // escapes: okay.\n")
+		g.emit("length, err := cc.CopyInBytes(addr, buf) // escapes: okay.\n")
 		g.emitKeepAlive(g.r)
 		g.emit("return length, err\n")
 	})
diff --git a/tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go b/tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go
index 39f654ea8..7edaf666c 100644
--- a/tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go
+++ b/tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go
@@ -154,11 +154,11 @@ func (g *interfaceGenerator) emitMarshallableForPrimitiveNewtype(nt *ast.Ident)
 
 	g.emit("// CopyOutN implements marshal.Marshallable.CopyOutN.\n")
 	g.emit("//go:nosplit\n")
-	g.emit("func (%s *%s) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
 		g.emitCastToByteSlice(g.r, "buf", fmt.Sprintf("%s.SizeBytes()", g.r))
 
-		g.emit("length, err := task.CopyOutBytes(addr, buf[:limit]) // escapes: okay.\n")
+		g.emit("length, err := cc.CopyOutBytes(addr, buf[:limit]) // escapes: okay.\n")
 		g.emitKeepAlive(g.r)
 		g.emit("return length, err\n")
 	})
@@ -166,19 +166,19 @@ func (g *interfaceGenerator) emitMarshallableForPrimitiveNewtype(nt *ast.Ident)
 
 	g.emit("// CopyOut implements marshal.Marshallable.CopyOut.\n")
 	g.emit("//go:nosplit\n")
-	g.emit("func (%s *%s) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
-		g.emit("return %s.CopyOutN(task, addr, %s.SizeBytes())\n", g.r, g.r)
+		g.emit("return %s.CopyOutN(cc, addr, %s.SizeBytes())\n", g.r, g.r)
 	})
 	g.emit("}\n\n")
 
 	g.emit("// CopyIn implements marshal.Marshallable.CopyIn.\n")
 	g.emit("//go:nosplit\n")
-	g.emit("func (%s *%s) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
 		g.emitCastToByteSlice(g.r, "buf", fmt.Sprintf("%s.SizeBytes()", g.r))
 
-		g.emit("length, err := task.CopyInBytes(addr, buf) // escapes: okay.\n")
+		g.emit("length, err := cc.CopyInBytes(addr, buf) // escapes: okay.\n")
 		g.emitKeepAlive(g.r)
 		g.emit("return length, err\n")
 	})
@@ -211,7 +211,7 @@ func (g *interfaceGenerator) emitMarshallableSliceForPrimitiveNewtype(nt *ast.Id
 
 	g.emit("// Copy%sIn copies in a slice of %s objects from the task's memory.\n", slice.ident, eltType)
 	g.emit("//go:nosplit\n")
-	g.emit("func Copy%sIn(task marshal.Task, addr usermem.Addr, dst []%s) (int, error) {\n", slice.ident, eltType)
+	g.emit("func Copy%sIn(cc marshal.CopyContext, addr usermem.Addr, dst []%s) (int, error) {\n", slice.ident, eltType)
 	g.inIndent(func() {
 		g.emit("count := len(dst)\n")
 		g.emit("if count == 0 {\n")
@@ -223,7 +223,7 @@ func (g *interfaceGenerator) emitMarshallableSliceForPrimitiveNewtype(nt *ast.Id
 
 		g.emitCastSliceToByteSlice("&dst", "buf", "size * count")
 
-		g.emit("length, err := task.CopyInBytes(addr, buf) // escapes: okay.\n")
+		g.emit("length, err := cc.CopyInBytes(addr, buf) // escapes: okay.\n")
 		g.emitKeepAlive("dst")
 		g.emit("return length, err\n")
 	})
@@ -231,7 +231,7 @@ func (g *interfaceGenerator) emitMarshallableSliceForPrimitiveNewtype(nt *ast.Id
 
 	g.emit("// Copy%sOut copies a slice of %s objects to the task's memory.\n", slice.ident, eltType)
 	g.emit("//go:nosplit\n")
-	g.emit("func Copy%sOut(task marshal.Task, addr usermem.Addr, src []%s) (int, error) {\n", slice.ident, eltType)
+	g.emit("func Copy%sOut(cc marshal.CopyContext, addr usermem.Addr, src []%s) (int, error) {\n", slice.ident, eltType)
 	g.inIndent(func() {
 		g.emit("count := len(src)\n")
 		g.emit("if count == 0 {\n")
@@ -243,7 +243,7 @@ func (g *interfaceGenerator) emitMarshallableSliceForPrimitiveNewtype(nt *ast.Id
 
 		g.emitCastSliceToByteSlice("&src", "buf", "size * count")
 
-		g.emit("length, err := task.CopyOutBytes(addr, buf) // escapes: okay.\n")
+		g.emit("length, err := cc.CopyOutBytes(addr, buf) // escapes: okay.\n")
 		g.emitKeepAlive("src")
 		g.emit("return length, err\n")
 	})
diff --git a/tools/go_marshal/gomarshal/generator_interfaces_struct.go b/tools/go_marshal/gomarshal/generator_interfaces_struct.go
index 44fbb425c..d3fc1c1c6 100644
--- a/tools/go_marshal/gomarshal/generator_interfaces_struct.go
+++ b/tools/go_marshal/gomarshal/generator_interfaces_struct.go
@@ -323,13 +323,13 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
 	g.emit("//go:nosplit\n")
 	g.recordUsedImport("marshal")
 	g.recordUsedImport("usermem")
-	g.emit("func (%s *%s) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
 		fallback := func() {
 			g.emit("// Type %s doesn't have a packed layout in memory, fall back to MarshalBytes.\n", g.typeName())
-			g.emit("buf := task.CopyScratchBuffer(%s.SizeBytes()) // escapes: okay.\n", g.r)
+			g.emit("buf := cc.CopyScratchBuffer(%s.SizeBytes()) // escapes: okay.\n", g.r)
 			g.emit("%s.MarshalBytes(buf) // escapes: fallback.\n", g.r)
-			g.emit("return task.CopyOutBytes(addr, buf[:limit]) // escapes: okay.\n")
+			g.emit("return cc.CopyOutBytes(addr, buf[:limit]) // escapes: okay.\n")
 		}
 		if thisPacked {
 			g.recordUsedImport("reflect")
@@ -343,7 +343,7 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
 			// Fast serialization.
 			g.emitCastToByteSlice(g.r, "buf", fmt.Sprintf("%s.SizeBytes()", g.r))
 
-			g.emit("length, err := task.CopyOutBytes(addr, buf[:limit]) // escapes: okay.\n")
+			g.emit("length, err := cc.CopyOutBytes(addr, buf[:limit]) // escapes: okay.\n")
 			g.emitKeepAlive(g.r)
 			g.emit("return length, err\n")
 		} else {
@@ -356,9 +356,9 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
 	g.emit("//go:nosplit\n")
 	g.recordUsedImport("marshal")
 	g.recordUsedImport("usermem")
-	g.emit("func (%s *%s) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
-		g.emit("return %s.CopyOutN(task, addr, %s.SizeBytes())\n", g.r, g.r)
+		g.emit("return %s.CopyOutN(cc, addr, %s.SizeBytes())\n", g.r, g.r)
 	})
 	g.emit("}\n\n")
 
@@ -366,12 +366,12 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
 	g.emit("//go:nosplit\n")
 	g.recordUsedImport("marshal")
 	g.recordUsedImport("usermem")
-	g.emit("func (%s *%s) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
+	g.emit("func (%s *%s) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {\n", g.r, g.typeName())
 	g.inIndent(func() {
 		fallback := func() {
 			g.emit("// Type %s doesn't have a packed layout in memory, fall back to UnmarshalBytes.\n", g.typeName())
-			g.emit("buf := task.CopyScratchBuffer(%s.SizeBytes()) // escapes: okay.\n", g.r)
-			g.emit("length, err := task.CopyInBytes(addr, buf) // escapes: okay.\n")
+			g.emit("buf := cc.CopyScratchBuffer(%s.SizeBytes()) // escapes: okay.\n", g.r)
+			g.emit("length, err := cc.CopyInBytes(addr, buf) // escapes: okay.\n")
 			g.emit("// Unmarshal unconditionally. If we had a short copy-in, this results in a\n")
 			g.emit("// partially unmarshalled struct.\n")
 			g.emit("%s.UnmarshalBytes(buf) // escapes: fallback.\n", g.r)
@@ -389,7 +389,7 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
 			// Fast deserialization.
 			g.emitCastToByteSlice(g.r, "buf", fmt.Sprintf("%s.SizeBytes()", g.r))
 
-			g.emit("length, err := task.CopyInBytes(addr, buf) // escapes: okay.\n")
+			g.emit("length, err := cc.CopyInBytes(addr, buf) // escapes: okay.\n")
 			g.emitKeepAlive(g.r)
 			g.emit("return length, err\n")
 		} else {
@@ -442,7 +442,7 @@ func (g *interfaceGenerator) emitMarshallableSliceForStruct(st *ast.StructType,
 	g.recordUsedImport("usermem")
 
 	g.emit("// Copy%sIn copies in a slice of %s objects from the task's memory.\n", slice.ident, g.typeName())
-	g.emit("func Copy%sIn(task marshal.Task, addr usermem.Addr, dst []%s) (int, error) {\n", slice.ident, g.typeName())
+	g.emit("func Copy%sIn(cc marshal.CopyContext, addr usermem.Addr, dst []%s) (int, error) {\n", slice.ident, g.typeName())
 	g.inIndent(func() {
 		g.emit("count := len(dst)\n")
 		g.emit("if count == 0 {\n")
@@ -454,8 +454,8 @@ func (g *interfaceGenerator) emitMarshallableSliceForStruct(st *ast.StructType,
 
 		fallback := func() {
 			g.emit("// Type %s doesn't have a packed layout in memory, fall back to UnmarshalBytes.\n", g.typeName())
-			g.emit("buf := task.CopyScratchBuffer(size * count)\n")
-			g.emit("length, err := task.CopyInBytes(addr, buf)\n\n")
+			g.emit("buf := cc.CopyScratchBuffer(size * count)\n")
+			g.emit("length, err := cc.CopyInBytes(addr, buf)\n\n")
 
 			g.emit("// Unmarshal as much as possible, even on error. First handle full objects.\n")
 			g.emit("limit := length/size\n")
@@ -489,7 +489,7 @@ func (g *interfaceGenerator) emitMarshallableSliceForStruct(st *ast.StructType,
 			// Fast deserialization.
 			g.emitCastSliceToByteSlice("&dst", "buf", "size * count")
 
-			g.emit("length, err := task.CopyInBytes(addr, buf)\n")
+			g.emit("length, err := cc.CopyInBytes(addr, buf)\n")
 			g.emitKeepAlive("dst")
 			g.emit("return length, err\n")
 		} else {
@@ -499,7 +499,7 @@ func (g *interfaceGenerator) emitMarshallableSliceForStruct(st *ast.StructType,
 	g.emit("}\n\n")
 
 	g.emit("// Copy%sOut copies a slice of %s objects to the task's memory.\n", slice.ident, g.typeName())
-	g.emit("func Copy%sOut(task marshal.Task, addr usermem.Addr, src []%s) (int, error) {\n", slice.ident, g.typeName())
+	g.emit("func Copy%sOut(cc marshal.CopyContext, addr usermem.Addr, src []%s) (int, error) {\n", slice.ident, g.typeName())
 	g.inIndent(func() {
 		g.emit("count := len(src)\n")
 		g.emit("if count == 0 {\n")
@@ -511,13 +511,13 @@ func (g *interfaceGenerator) emitMarshallableSliceForStruct(st *ast.StructType,
 
 		fallback := func() {
 			g.emit("// Type %s doesn't have a packed layout in memory, fall back to MarshalBytes.\n", g.typeName())
-			g.emit("buf := task.CopyScratchBuffer(size * count)\n")
+			g.emit("buf := cc.CopyScratchBuffer(size * count)\n")
 			g.emit("for idx := 0; idx < count; idx++ {\n")
 			g.inIndent(func() {
 				g.emit("src[idx].MarshalBytes(buf[size*idx:size*(idx+1)])\n")
 			})
 			g.emit("}\n")
-			g.emit("return task.CopyOutBytes(addr, buf)\n")
+			g.emit("return cc.CopyOutBytes(addr, buf)\n")
 		}
 		if thisPacked {
 			g.recordUsedImport("reflect")
@@ -531,7 +531,7 @@ func (g *interfaceGenerator) emitMarshallableSliceForStruct(st *ast.StructType,
 			// Fast serialization.
 			g.emitCastSliceToByteSlice("&src", "buf", "size * count")
 
-			g.emit("length, err := task.CopyOutBytes(addr, buf)\n")
+			g.emit("length, err := cc.CopyOutBytes(addr, buf)\n")
 			g.emitKeepAlive("src")
 			g.emit("return length, err\n")
 		} else {
diff --git a/tools/go_marshal/test/escape/escape.go b/tools/go_marshal/test/escape/escape.go
index ff23d87d1..7f62b0a2b 100644
--- a/tools/go_marshal/test/escape/escape.go
+++ b/tools/go_marshal/test/escape/escape.go
@@ -20,29 +20,29 @@ import (
 	"gvisor.dev/gvisor/tools/go_marshal/test"
 )
 
-// dummyTask implements marshal.Task.
-type dummyTask struct {
+// dummyCopyContext implements marshal.CopyContext.
+type dummyCopyContext struct {
 }
 
-func (*dummyTask) CopyScratchBuffer(size int) []byte {
+func (*dummyCopyContext) CopyScratchBuffer(size int) []byte {
 	return make([]byte, size)
 }
 
-func (*dummyTask) CopyOutBytes(addr usermem.Addr, b []byte) (int, error) {
+func (*dummyCopyContext) CopyOutBytes(addr usermem.Addr, b []byte) (int, error) {
 	return len(b), nil
 }
 
-func (*dummyTask) CopyInBytes(addr usermem.Addr, b []byte) (int, error) {
+func (*dummyCopyContext) CopyInBytes(addr usermem.Addr, b []byte) (int, error) {
 	return len(b), nil
 }
 
-func (t *dummyTask) MarshalBytes(addr usermem.Addr, marshallable marshal.Marshallable) {
+func (t *dummyCopyContext) MarshalBytes(addr usermem.Addr, marshallable marshal.Marshallable) {
 	buf := t.CopyScratchBuffer(marshallable.SizeBytes())
 	marshallable.MarshalBytes(buf)
 	t.CopyOutBytes(addr, buf)
 }
 
-func (t *dummyTask) MarshalUnsafe(addr usermem.Addr, marshallable marshal.Marshallable) {
+func (t *dummyCopyContext) MarshalUnsafe(addr usermem.Addr, marshallable marshal.Marshallable) {
 	buf := t.CopyScratchBuffer(marshallable.SizeBytes())
 	marshallable.MarshalUnsafe(buf)
 	t.CopyOutBytes(addr, buf)
@@ -50,14 +50,14 @@ func (t *dummyTask) MarshalUnsafe(addr usermem.Addr, marshallable marshal.Marsha
 
 // +checkescape:all
 //go:nosplit
-func doCopyIn(t *dummyTask) {
+func doCopyIn(t *dummyCopyContext) {
 	var stat test.Stat
 	stat.CopyIn(t, usermem.Addr(0xf000ba12))
 }
 
 // +checkescape:all
 //go:nosplit
-func doCopyOut(t *dummyTask) {
+func doCopyOut(t *dummyCopyContext) {
 	var stat test.Stat
 	stat.CopyOut(t, usermem.Addr(0xf000ba12))
 }
@@ -65,7 +65,7 @@ func doCopyOut(t *dummyTask) {
 // +mustescape:builtin
 // +mustescape:stack
 //go:nosplit
-func doMarshalBytesDirect(t *dummyTask) {
+func doMarshalBytesDirect(t *dummyCopyContext) {
 	var stat test.Stat
 	buf := t.CopyScratchBuffer(stat.SizeBytes())
 	stat.MarshalBytes(buf)
@@ -75,7 +75,7 @@ func doMarshalBytesDirect(t *dummyTask) {
 // +mustescape:builtin
 // +mustescape:stack
 //go:nosplit
-func doMarshalUnsafeDirect(t *dummyTask) {
+func doMarshalUnsafeDirect(t *dummyCopyContext) {
 	var stat test.Stat
 	buf := t.CopyScratchBuffer(stat.SizeBytes())
 	stat.MarshalUnsafe(buf)
@@ -85,7 +85,7 @@ func doMarshalUnsafeDirect(t *dummyTask) {
 // +mustescape:local,heap
 // +mustescape:stack
 //go:nosplit
-func doMarshalBytesViaMarshallable(t *dummyTask) {
+func doMarshalBytesViaMarshallable(t *dummyCopyContext) {
 	var stat test.Stat
 	t.MarshalBytes(usermem.Addr(0xf000ba12), &stat)
 }
@@ -93,7 +93,7 @@ func doMarshalBytesViaMarshallable(t *dummyTask) {
 // +mustescape:local,heap
 // +mustescape:stack
 //go:nosplit
-func doMarshalUnsafeViaMarshallable(t *dummyTask) {
+func doMarshalUnsafeViaMarshallable(t *dummyCopyContext) {
 	var stat test.Stat
 	t.MarshalUnsafe(usermem.Addr(0xf000ba12), &stat)
 }
diff --git a/tools/go_marshal/test/marshal_test.go b/tools/go_marshal/test/marshal_test.go
index 7c3481ac8..a00f9a684 100644
--- a/tools/go_marshal/test/marshal_test.go
+++ b/tools/go_marshal/test/marshal_test.go
@@ -36,13 +36,13 @@ import (
 
 var simulatedErr error = syserror.EFAULT
 
-// mockTask implements marshal.Task.
-type mockTask struct {
+// mockCopyContext implements marshal.CopyContext.
+type mockCopyContext struct {
 	taskMem usermem.BytesIO
 }
 
 // populate fills the task memory with the contents of val.
-func (t *mockTask) populate(val interface{}) {
+func (t *mockCopyContext) populate(val interface{}) {
 	var buf bytes.Buffer
 	// Use binary.Write so we aren't testing go-marshal against its own
 	// potentially buggy implementation.
@@ -52,7 +52,7 @@ func (t *mockTask) populate(val interface{}) {
 	t.taskMem.Bytes = buf.Bytes()
 }
 
-func (t *mockTask) setLimit(n int) {
+func (t *mockCopyContext) setLimit(n int) {
 	if len(t.taskMem.Bytes) < n {
 		grown := make([]byte, n)
 		copy(grown, t.taskMem.Bytes)
@@ -62,22 +62,22 @@ func (t *mockTask) setLimit(n int) {
 	t.taskMem.Bytes = t.taskMem.Bytes[:n]
 }
 
-// CopyScratchBuffer implements marshal.Task.CopyScratchBuffer.
-func (t *mockTask) CopyScratchBuffer(size int) []byte {
+// CopyScratchBuffer implements marshal.CopyContext.CopyScratchBuffer.
+func (t *mockCopyContext) CopyScratchBuffer(size int) []byte {
 	return make([]byte, size)
 }
 
-// CopyOutBytes implements marshal.Task.CopyOutBytes. The implementation
+// CopyOutBytes implements marshal.CopyContext.CopyOutBytes. The implementation
 // completely ignores the target address and stores a copy of b in its
 // internally buffer, overriding any previous contents.
-func (t *mockTask) CopyOutBytes(_ usermem.Addr, b []byte) (int, error) {
+func (t *mockCopyContext) CopyOutBytes(_ usermem.Addr, b []byte) (int, error) {
 	return t.taskMem.CopyOut(nil, 0, b, usermem.IOOpts{})
 }
 
-// CopyInBytes implements marshal.Task.CopyInBytes. The implementation
+// CopyInBytes implements marshal.CopyContext.CopyInBytes. The implementation
 // completely ignores the source address and always fills b from the begining of
 // its internal buffer.
-func (t *mockTask) CopyInBytes(_ usermem.Addr, b []byte) (int, error) {
+func (t *mockCopyContext) CopyInBytes(_ usermem.Addr, b []byte) (int, error) {
 	return t.taskMem.CopyIn(nil, 0, b, usermem.IOOpts{})
 }
 
@@ -171,11 +171,11 @@ func compareMemory(t *testing.T, expected, actual []byte, n int) {
 // dst. The task signals an error at limit bytes during copy-in, which should
 // result in a truncated unmarshalling.
 func limitedCopyIn(t *testing.T, src, dst marshal.Marshallable, limit int) {
-	var task mockTask
-	task.populate(src)
-	task.setLimit(limit)
+	var cc mockCopyContext
+	cc.populate(src)
+	cc.setLimit(limit)
 
-	n, err := dst.CopyIn(&task, usermem.Addr(0))
+	n, err := dst.CopyIn(&cc, usermem.Addr(0))
 	if n != limit {
 		t.Errorf("CopyIn copied unexpected number of bytes, expected %d, got %d", limit, n)
 	}
@@ -202,10 +202,10 @@ func limitedCopyIn(t *testing.T, src, dst marshal.Marshallable, limit int) {
 // limitedCopyOut marshals src to task memory. The task signals an error at
 // limit bytes during copy-out, which should result in a truncated marshalling.
 func limitedCopyOut(t *testing.T, src marshal.Marshallable, limit int) {
-	var task mockTask
-	task.setLimit(limit)
+	var cc mockCopyContext
+	cc.setLimit(limit)
 
-	n, err := src.CopyOut(&task, usermem.Addr(0))
+	n, err := src.CopyOut(&cc, usermem.Addr(0))
 	if n != limit {
 		t.Errorf("CopyOut copied unexpected number of bytes, expected %d, got %d", limit, n)
 	}
@@ -215,7 +215,7 @@ func limitedCopyOut(t *testing.T, src marshal.Marshallable, limit int) {
 
 	expectedMem := unsafeMemory(src)
 	defer runtime.KeepAlive(src)
-	actualMem := task.taskMem.Bytes
+	actualMem := cc.taskMem.Bytes
 
 	compareMemory(t, expectedMem, actualMem, n)
 }
@@ -223,10 +223,10 @@ func limitedCopyOut(t *testing.T, src marshal.Marshallable, limit int) {
 // copyOutN marshals src to task memory, requesting the marshalling to be
 // limited to limit bytes.
 func copyOutN(t *testing.T, src marshal.Marshallable, limit int) {
-	var task mockTask
-	task.setLimit(limit)
+	var cc mockCopyContext
+	cc.setLimit(limit)
 
-	n, err := src.CopyOutN(&task, usermem.Addr(0), limit)
+	n, err := src.CopyOutN(&cc, usermem.Addr(0), limit)
 	if err != nil {
 		t.Errorf("CopyOut returned unexpected error: %v", err)
 	}
@@ -236,7 +236,7 @@ func copyOutN(t *testing.T, src marshal.Marshallable, limit int) {
 
 	expectedMem := unsafeMemory(src)
 	defer runtime.KeepAlive(src)
-	actualMem := task.taskMem.Bytes
+	actualMem := cc.taskMem.Bytes
 
 	t.Logf("Expected: %v + %v\n", expectedMem[:n], expectedMem[n:])
 	t.Logf("Actual  : %v + %v\n", actualMem[:n], actualMem[n:])
@@ -303,20 +303,20 @@ func TestLimitedMarshalling(t *testing.T) {
 func TestLimitedSliceMarshalling(t *testing.T) {
 	types := []struct {
 		arrayPtrType reflect.Type
-		copySliceIn  func(task marshal.Task, addr usermem.Addr, dstSlice interface{}) (int, error)
-		copySliceOut func(task marshal.Task, addr usermem.Addr, srcSlice interface{}) (int, error)
+		copySliceIn  func(cc marshal.CopyContext, addr usermem.Addr, dstSlice interface{}) (int, error)
+		copySliceOut func(cc marshal.CopyContext, addr usermem.Addr, srcSlice interface{}) (int, error)
 		unsafeMemory func(arrPtr interface{}) []byte
 	}{
 		// Packed types.
 		{
 			reflect.TypeOf((*[20]test.Stat)(nil)),
-			func(task marshal.Task, addr usermem.Addr, dst interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, dst interface{}) (int, error) {
 				slice := dst.(*[20]test.Stat)[:]
-				return test.CopyStatSliceIn(task, addr, slice)
+				return test.CopyStatSliceIn(cc, addr, slice)
 			},
-			func(task marshal.Task, addr usermem.Addr, src interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, src interface{}) (int, error) {
 				slice := src.(*[20]test.Stat)[:]
-				return test.CopyStatSliceOut(task, addr, slice)
+				return test.CopyStatSliceOut(cc, addr, slice)
 			},
 			func(a interface{}) []byte {
 				slice := a.(*[20]test.Stat)[:]
@@ -325,13 +325,13 @@ func TestLimitedSliceMarshalling(t *testing.T) {
 		},
 		{
 			reflect.TypeOf((*[1]test.Stat)(nil)),
-			func(task marshal.Task, addr usermem.Addr, dst interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, dst interface{}) (int, error) {
 				slice := dst.(*[1]test.Stat)[:]
-				return test.CopyStatSliceIn(task, addr, slice)
+				return test.CopyStatSliceIn(cc, addr, slice)
 			},
-			func(task marshal.Task, addr usermem.Addr, src interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, src interface{}) (int, error) {
 				slice := src.(*[1]test.Stat)[:]
-				return test.CopyStatSliceOut(task, addr, slice)
+				return test.CopyStatSliceOut(cc, addr, slice)
 			},
 			func(a interface{}) []byte {
 				slice := a.(*[1]test.Stat)[:]
@@ -340,13 +340,13 @@ func TestLimitedSliceMarshalling(t *testing.T) {
 		},
 		{
 			reflect.TypeOf((*[5]test.SignalSetAlias)(nil)),
-			func(task marshal.Task, addr usermem.Addr, dst interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, dst interface{}) (int, error) {
 				slice := dst.(*[5]test.SignalSetAlias)[:]
-				return test.CopySignalSetAliasSliceIn(task, addr, slice)
+				return test.CopySignalSetAliasSliceIn(cc, addr, slice)
 			},
-			func(task marshal.Task, addr usermem.Addr, src interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, src interface{}) (int, error) {
 				slice := src.(*[5]test.SignalSetAlias)[:]
-				return test.CopySignalSetAliasSliceOut(task, addr, slice)
+				return test.CopySignalSetAliasSliceOut(cc, addr, slice)
 			},
 			func(a interface{}) []byte {
 				slice := a.(*[5]test.SignalSetAlias)[:]
@@ -356,13 +356,13 @@ func TestLimitedSliceMarshalling(t *testing.T) {
 		// Non-packed types.
 		{
 			reflect.TypeOf((*[20]test.Type1)(nil)),
-			func(task marshal.Task, addr usermem.Addr, dst interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, dst interface{}) (int, error) {
 				slice := dst.(*[20]test.Type1)[:]
-				return test.CopyType1SliceIn(task, addr, slice)
+				return test.CopyType1SliceIn(cc, addr, slice)
 			},
-			func(task marshal.Task, addr usermem.Addr, src interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, src interface{}) (int, error) {
 				slice := src.(*[20]test.Type1)[:]
-				return test.CopyType1SliceOut(task, addr, slice)
+				return test.CopyType1SliceOut(cc, addr, slice)
 			},
 			func(a interface{}) []byte {
 				slice := a.(*[20]test.Type1)[:]
@@ -371,13 +371,13 @@ func TestLimitedSliceMarshalling(t *testing.T) {
 		},
 		{
 			reflect.TypeOf((*[1]test.Type1)(nil)),
-			func(task marshal.Task, addr usermem.Addr, dst interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, dst interface{}) (int, error) {
 				slice := dst.(*[1]test.Type1)[:]
-				return test.CopyType1SliceIn(task, addr, slice)
+				return test.CopyType1SliceIn(cc, addr, slice)
 			},
-			func(task marshal.Task, addr usermem.Addr, src interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, src interface{}) (int, error) {
 				slice := src.(*[1]test.Type1)[:]
-				return test.CopyType1SliceOut(task, addr, slice)
+				return test.CopyType1SliceOut(cc, addr, slice)
 			},
 			func(a interface{}) []byte {
 				slice := a.(*[1]test.Type1)[:]
@@ -386,13 +386,13 @@ func TestLimitedSliceMarshalling(t *testing.T) {
 		},
 		{
 			reflect.TypeOf((*[7]test.Type8)(nil)),
-			func(task marshal.Task, addr usermem.Addr, dst interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, dst interface{}) (int, error) {
 				slice := dst.(*[7]test.Type8)[:]
-				return test.CopyType8SliceIn(task, addr, slice)
+				return test.CopyType8SliceIn(cc, addr, slice)
 			},
-			func(task marshal.Task, addr usermem.Addr, src interface{}) (int, error) {
+			func(cc marshal.CopyContext, addr usermem.Addr, src interface{}) (int, error) {
 				slice := src.(*[7]test.Type8)[:]
-				return test.CopyType8SliceOut(task, addr, slice)
+				return test.CopyType8SliceOut(cc, addr, slice)
 			},
 			func(a interface{}) []byte {
 				slice := a.(*[7]test.Type8)[:]
@@ -439,11 +439,11 @@ func TestLimitedSliceMarshalling(t *testing.T) {
 			limit += elem.SizeBytes() / 2
 			analysis.RandomizeValue(expected)
 
-			var task mockTask
-			task.populate(expected)
-			task.setLimit(limit)
+			var cc mockCopyContext
+			cc.populate(expected)
+			cc.setLimit(limit)
 
-			n, err := tt.copySliceIn(&task, usermem.Addr(0), actual)
+			n, err := tt.copySliceIn(&cc, usermem.Addr(0), actual)
 			if n != limit {
 				t.Errorf("CopyIn copied unexpected number of bytes, expected %d, got %d", limit, n)
 			}
@@ -493,11 +493,11 @@ func TestLimitedSliceMarshalling(t *testing.T) {
 			limit += elem.SizeBytes() / 2
 			analysis.RandomizeValue(expected)
 
-			var task mockTask
-			task.populate(expected)
-			task.setLimit(limit)
+			var cc mockCopyContext
+			cc.populate(expected)
+			cc.setLimit(limit)
 
-			n, err := tt.copySliceOut(&task, usermem.Addr(0), expected)
+			n, err := tt.copySliceOut(&cc, usermem.Addr(0), expected)
 			if n != limit {
 				t.Errorf("CopyIn copied unexpected number of bytes, expected %d, got %d", limit, n)
 			}
@@ -507,7 +507,7 @@ func TestLimitedSliceMarshalling(t *testing.T) {
 
 			expectedMem := tt.unsafeMemory(expected)
 			defer runtime.KeepAlive(expected)
-			actualMem := task.taskMem.Bytes
+			actualMem := cc.taskMem.Bytes
 
 			compareMemory(t, expectedMem, actualMem, n)
 		})