needIdxBase, needIdxLimit := addrRangeToSummaryRange(l, makeAddrRange(base, limit))

		// Update the summary slices with a new upper-bound. This ensures
		// we get tight bounds checks on at least the top bound.
		//
		// We must do this regardless of whether we map new memory.
		if needIdxLimit > len(p.summary[l]) {
			p.summary[l] = p.summary[l][:needIdxLimit]
		}