golang/go · error

error processing pprof PGO profile: %w

Error message

error processing pprof PGO profile: %w

What it means

When the PGO profile is in pprof format, the compiler calls pgo.FromPProf to parse the protobuf-encoded profile data. This error wraps any parsing failure, indicating the pprof data is malformed, contains invalid protobuf, or has structural inconsistencies.

Source

Thrown at src/cmd/compile/internal/pgoir/irgraph.go:144

	}
	defer f.Close()
	r := bufio.NewReader(f)

	isSerialized, err := pgo.IsSerialized(r)
	if err != nil {
		return nil, fmt.Errorf("error processing profile header: %w", err)
	}

	var base *pgo.Profile
	if isSerialized {
		base, err = pgo.FromSerialized(r)
		if err != nil {
			return nil, fmt.Errorf("error processing serialized PGO profile: %w", err)
		}
	} else {
		base, err = pgo.FromPProf(r)
		if err != nil {
			return nil, fmt.Errorf("error processing pprof PGO profile: %w", err)
		}
	}

	if base.TotalWeight == 0 {
		return nil, nil // accept but ignore profile with no samples.
	}

	// Create package-level call graph with weights from profile and IR.
	wg := createIRGraph(base.NamedEdgeMap)

	return &Profile{
		Profile:    base,
		WeightedCG: wg,
	}, nil
}

// createIRGraph builds the IRGraph by visiting all the ir.Func in decl list
// of a package.

View on GitHub (pinned to b6b368adc5)

Solutions

1. Regenerate the profile from scratch: go test -cpuprofile=default.pgo ./...
2. Validate the profile opens correctly: go tool pprof -top default.pgo
3. Ensure the profiling process ran to completion without being killed
4. Check available disk space and memory during profiling

// Validate a pprof profile using the pprof tool chain
func validatePprofProfile(path string) error {
    f, err := os.Open(path)
    if err != nil {
        return err
    }
    defer f.Close()
    // pprof files are gzip-compressed protobuf; check for gzip header
    header := make([]byte, 2)
    if _, err := io.ReadFull(f, header); err != nil {
        return fmt.Errorf("cannot read profile header: %w", err)
    }
    if header[0] != 0x1f || header[1] != 0x8b {
        return fmt.Errorf("not a gzip-compressed pprof profile")
    }
    return nil
}

When it happens

Trigger: Passing a file that has a pprof magic number but contains corrupted or invalid protobuf data. Profiles from incompatible pprof implementations. Profiles that were truncated during generation.

Common situations: Profiles generated by interrupted profiling sessions (timeout, OOM kill, signal). Profiles from non-standard profiling tools that produce partial pprof output. Manual editing of profile files.

Related errors

• error processing profile header: %w
• error processing serialized PGO profile: %w
• error opening profile: %w
• error parsing profile: %w
• no DWARF data in go object file

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/fcd8bf516c4b38b4. Report an issue: GitHub.