c - Valgrind 错误可能与 c 中的 malloc 有关

Question

我的代码有问题。我收到 valgrind 错误，这与 malloc 有关。我很困惑，因为我对代码的其他部分没有任何问题，这些部分与我遇到问题的部分完全相同。我得到的错误是:

==15151==    at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)                                                          
==15151==    by 0x4006E2: main (additup.c:28)




struct bigInt {
      int digit;
      struct bigInt *next;
      struct bigInt *prev;
};

struct bigInt* curInt;
struct bigInt* intHead;
struct bigInt* intTail;
struct bigInt* curSum;
struct bigInt* sumHead;
struct bigInt* sumTail;

int main(){
  int addSum(int i );
  curInt = malloc(sizeof(struct bigInt));
  intHead = malloc(sizeof(struct bigInt));
  intTail = malloc(sizeof(struct bigInt));
  curSum = malloc(sizeof(struct bigInt)); // Problem: line 28
  sumHead = malloc(sizeof(struct bigInt)); //Problem: line 29
  sumTail = malloc(sizeof(struct bigInt));  //Problem: line 30
  addSum(11); //add head to sum linked list
  addSum(99);//add tail to sum linked list
  addSum(0);

int addSum(int i){ //adds sum  structure to front of linked list
  struct bigInt* x = malloc(sizeof(struct bigInt));
  if(i==11){
    x->digit=i;
    sumHead=x;
    curSum=x;
  } else {
    x->next=sumHead->next;
    sumHead->next=x;
    x->prev=sumHead;
    curSum=x;
    x->digit=i; 
  if(i==99) sumTail=x;
  }
  return 0;
}

如有任何帮助，我们将不胜感激。谢谢`

Answer 1

 addSum(99);//add tail to sum linked list
//...
  if(i==99) sumTail=x;

那是内存泄漏。 sumTail 指向的先前 malloc block 不再可访问。 ...另外两个方 block 也以同样的方式丢失。