// do have to handle the negative credit case.
	bgScanCredit := gcController.bgScanCredit.Load()
	stolen := int64(0)
	if bgScanCredit > 0 {
		if bgScanCredit < scanWork {
			stolen = bgScanCredit
			gp.gcAssistBytes += 1 + int64(assistBytesPerWork*float64(stolen))
		} else {
			stolen = scanWork
			gp.gcAssistBytes += debtBytes
		}
		gcController.bgScanCredit.Add(-stolen)

		scanWork -= stolen

	stackScanWork   atomic.Int64
	globalsScanWork atomic.Int64

	// bgScanCredit is the scan work credit accumulated by the concurrent
	// background scan. This credit is accumulated by the background scan
	// and stolen by mutator assists.  Updates occur in bounded batches,
	// since it is both written and read throughout the cycle.
	bgScanCredit atomic.Int64

	// assistTime is the nanoseconds spent in mutator assists

		// rapidly creating an exiting goroutines.
		assistWorkPerByte := gcController.assistWorkPerByte.Load()
		scanCredit := int64(assistWorkPerByte * float64(gp.gcAssistBytes))
		gcController.bgScanCredit.Add(scanCredit)
		gp.gcAssistBytes = 0
	}

	dropg()

	if GOARCH == "wasm" { // no threads yet on wasm
		gfput(pp, gp)
		return
	}

	if locked && mp.lockedInt != 0 {