FUTEX_ROBUST_MOD_MASK
*entry = (void __user *)(uentry & ~FUTEX_ROBUST_MOD_MASK);
*mod = uentry & FUTEX_ROBUST_MOD_MASK;
*entry = compat_ptr((*uentry) & ~FUTEX_ROBUST_MOD_MASK);
*pflags = (unsigned int)(*uentry) & FUTEX_ROBUST_MOD_MASK;