What causes "MemoryMap not supported" in go-delve/delve?

Handle the sentinel with errors.Is(err, proc.ErrMemoryMapNotSupported) and skip address-range validation.

MemoryMap not supported

Error message

MemoryMap not supported

What it means

ErrMemoryMapNotSupported (pkg/proc/dump.go:17) is returned by the MemoryMap API when the active backend cannot enumerate memory regions. Core-dump backends that lack region metadata (or backends like gdbserial/live targets where the map is unavailable) return this sentinel instead of a map.

Source

Thrown at pkg/proc/dump.go:17

package proc

import (
	"bytes"
	"debug/elf"
	"encoding/binary"
	"errors"
	"fmt"
	"runtime"
	"sync"

	"github.com/go-delve/delve/pkg/elfwriter"
	"github.com/go-delve/delve/pkg/version"
)

var (
	ErrMemoryMapNotSupported = errors.New("MemoryMap not supported")
)

// DumpState represents the current state of a core dump in progress.
type DumpState struct {
	Mutex sync.Mutex

	Dumping  bool
	AllDone  bool
	Canceled bool
	DoneChan chan struct{}

	ThreadsDone, ThreadsTotal int
	MemDone, MemTotal         uint64

	Err error
}

// DumpFlags is used to configure (*Target).Dump

View on GitHub (pinned to a23773e6c3)

Solutions

Handle the sentinel with errors.Is(err, proc.ErrMemoryMapNotSupported) and skip address-range validation.
Derive memory regions from the ELF program headers of the core file yourself (readelf -l core).
Use a live debug session or a full Linux core (not a reduced minidump) if the memory map is required.
Check your delve version/backend; some backends may add MemoryMap support in newer releases.

Example fix

// before
regions, err := proc.MemoryMap(...) // panic-free but breaks on minidumps

// after
regions, err := proc.MemoryMap(...)
if errors.Is(err, proc.ErrMemoryMapNotSupported) {
    regions = parsePTLoad(coreFile) // fall back to ELF headers
}

Defensive patterns

Strategy: fallback

Validate before calling

_, err := proc0.MemoryMap()
memMapOK := !errors.Is(err, proc.ErrMemoryMapNotSupported)

Type guard

func memoryMapSupported(err error) bool { return !errors.Is(err, proc.ErrMemoryMapNotSupported) }

Try / catch

regions, err := p.MemoryMap()
if errors.Is(err, proc.ErrMemoryMapNotSupported) {
    regions = regionsFromPTLoad(coreFile) // derive from ELF headers
}

Prevention

Feature-detect MemoryMap support once at session start.
Parse the core's ELF program headers as a region source alternative.
Avoid address-range validation logic that assumes a memory map exists.
Use full Linux cores rather than reduced minidumps when region info matters.

When it happens

Trigger: Calling MemoryMap (or the rpc2 equivalent, e.g. 'info mem'-style clients) on a process whose backend does not implement memory-map enumeration, such as certain core dump or minidump opens.

Common situations: Tooling that queries the memory map for address-validity heuristics against a minidump; scripts that work on Linux live targets then run against core files; IDE memory-map panels opened in a core session.

Related errors

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/de76367e16493d6d. Report an issue: GitHub.