A DESCRIPTION OF THE PROBLEM :
if (check >= 0) {
            Node<K,V>[] tab, nt; int n, sc;
            while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
                   (n = tab.length) < MAXIMUM_CAPACITY) {
                int rs = resizeStamp(n);
                if (sc < 0) {
                    if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
                        sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
                        transferIndex <= 0)
                        break;
                    if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1))
                        transfer(tab, nt);
                }
                else if (U.compareAndSetInt(this, SIZECTL, sc,
                                             (rs << RESIZE_STAMP_SHIFT) + 2))
                    transfer(tab, null);
                s = sumCount();
            }
        }

In the above code, condition of (sc == rs + 1 || sc == rs + MAX_RESIZERS ) would never be true , since the value of rs is positive and the value of sc is negative .

The correct condition should be (sc >>> RESIZE_STAMP_SHIFT) == rs + 1 || (sc >>> RESIZE_STAMP_SHIFT) == rs + MAX_RESIZERS, which can be used to dedect if resizing process finished or resizing threads reaches maxmium limitation

if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
                        sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
                        transferIndex <= 0)


FREQUENCY : always


Edited to correct apparent typo: it stated "... the value of rs is negative" but it is sc that is negative.