segmentation-fault - 调用函数时出现分段错误（核心转储错误）

Question

我在函数调用中遇到核心转储错误，该错误应该返回一个。该函数正在传递一个向量元素，该向量元素是指向结构的指针，作为函数的参数，但作为返回结果是核心转储。

struct block
{
  int64_t tag;
  bool valid_bit;
  bool dirty_bit;
  block* next;
  block* prev;
};

vector< block* > cash_set;

……

int main (int argc, const char *argv[])
{
  int findcash;

.....
if (cash_type == 1)
    {
      cout<<"\n Fully Associative";
      number_of_blocks = cash_size / block_size;
    
cout<<"\n Enter the Replacement Policy \n 0 for Random\n 1 for LRU\n 2 for Pseudo LRU\n";
      cin>>Replacement_policy;
// initializing the cache to valid bit as 0 and dirty bit as 0
      int   i;
      cash_set.push_back(NULL);
      //Reading file "traces.txt"
      associativity=number_of_blocks;         
      int loc;
      newfile.open ("traces.txt", ios::in); 
      //open a file to perform read operation using file object
    if (newfile.is_open ())
            {           //checking whether the file is open
                 int    count = 0;
                 while (getline (newfile, tp))
                 {
                    cash_access++;
                    iss.str (tp);
              //read data from file object and put it into string.
                   cout << "\n" << count++ << " " << tp << "\n";    
                   
                   //print the data of the string
    
                    iss >> std::hex >> addr;
                    cout << "  Address:" << addr << "\t";
                    operation = tp.substr (11, 1);
                    cout << operation << "\n";
              //extracting Tag, Index from the address
                    shift = log2 (block_size);
                    index_addr = (addr >> shift) % number_of_blocks;
                    cout<<"done\n";
                    shift = log2 (number_of_blocks + block_size);
                    tag_addr = addr >> shift;
                    findcash=find(cash_set[0],tag_addr);
//after the above line of code it gives Core dump 
                        
                        cout<<"\nfindcache:"<<findcash;  

查找功能如下——

int find(block* tmp,int64_t tag1)
{
    **if(tmp==NULL)
    {
    compulsry_misses++;
    cout<<"Cumpolsary miss:"<<compulsry_misses;
    return 0;
    }**
    else
    {
        block* cashblock=tmp;
        while(tmp->prev!=NULL)
        {
// Cache Hit. Bring the accessed node to the front of the DLL         
            if (tmp->tag==tag1)
            {
                    cout<<"\n Cache Hit"<<cash_hit;
                    (tmp->next)->prev=tmp->prev;
                    (tmp->prev)->next=tmp->next;
                    cashblock->next=tmp;
                    tmp->prev=cashblock;
                    tmp->next=NULL;
                    cashblock->next=tmp;
                    cashblock=tmp;
                    return 1;
            }
            tmp=tmp->prev;
        }
    return 0;
    }   
}

Traces.txt 文件包含以下数据 -

0x6b8b4567 w
0x327b23c6 r
0x643c9869 w
0x66334873 r
0x74b0dc51 w
0x19495cff r
0x2ae8944a w
......

在 Ubuntu 上运行代码后的输出如下 -

....    
Fully Associative
     Enter the Replacement Policy 
     0 for Random
     1 for LRU
     2 for Pseudo LRU
    0
    
    0 0x6b8b4567 w
      Address:1804289383    w
    done
    Cumpolsary miss:1
    Segmentation fault (core dumped)

标签： segmentation-fault