??????????????漰??????Linux????????????????????????κε???

?????????????????????????????????????????? ???????????????????????pthread_attr_setstack??????????????????С????????task_struct?? mm_struct *mm ?????????????????stack_size???????????????????С???

???????????

????????????????????task_struct ??mm_struct *mm?????????? mm?е???????????????????????????? ?????????????STACK_TOP?? ?????????PF_RANDOMIZE????????????????С?????????????????????????STACK_TOP?? ????????????TASK_SIZE?? ??32λ???????0XC0000000??????????????????????????????????mm->start_stack?У????????cat /proc/xxx/stat ????

?????????????????????????????????????????????mm->mmap_base??mm->mmap_base???????mmap_base????????????????????????mmap?????????????????????????????????????mmap_base????????????￡?

#define MIN_GAP (128*1024*1024)
#define MAX_GAP (TASK_SIZE/6*5)
static inline unsigned long mmap_base(struct mm_struct *mm)
{
  unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur; // rlim_cur ????8388608????8M?? ??????? getrlimit(RLIMIT_STACK?? &limit) ??
  unsigned long random_factor = 0;
  if (current->flags & PF_RANDOMIZE)
    random_factor = get_random_int() % (1024*1024);
  if (gap < MIN_GAP) // ???MIN_GAP???????????????С?????128MB
    gap = MIN_GAP;
  else if (gap > MAX_GAP) // ???????TASK_SIZE/6*5?? ??2.5G
    gap = MAX_GAP;
  return PAGE_ALIGN(TASK_SIZE - gap - random_factor); // ???????random_factor????С?????????????
}

? ? IA-32????????????????????

??????????

??????????????????????л????????????????а????????б?????????ID????????????????????????????????????????errno????????????????????????????????y???????????????????????????е????????????????????????棬???????????????????????mm_struct *mm????????????????mm???????????