双链表分段故障c

Question

对于下面的代码，我尝试使用null head和null tail实现双向链表的insert函数。由于某种原因，程序不断出现看似随机的seg错误，并且没有进入正确的 if 或 elseif 语句。这是有问题的代码和终端输出：

void Insert(struct list_s* list, char* val) {
   struct list_node_s* temp_p;
   struct list_node_s* curr_p = list->h_p;
   struct list_node_s* prev_p = NULL;
   temp_p = Allocate_node(sizeof(val));
   temp_p->data = val;



 while (curr_p != NULL){
      if (strcmp(curr_p->data, val) > 0){
         prev_p = curr_p;
         curr_p = curr_p->next_p;
      }
      else if (strcmp(curr_p->data, val) < 0){
         break;
      }
      else{
         printf("Thats already in the list!\n");
         break;
      }
   }
   printf("while\n");

   if (list->h_p == NULL){ //none are in list
      printf("here1\n");
      list->h_p = temp_p;
      list->t_p = temp_p;
   }
   else if (curr_p->next_p == NULL){ //if end of list
      printf("here2\n");
      curr_p->next_p = temp_p;
      temp_p->pred_p = curr_p;
      list->t_p = temp_p;
   }

   else{
      printf("here3\n");
      temp_p->next_p = curr_p;
      curr_p->pred_p = temp_p;
      temp_p->pred_p = prev_p;
      prev_p->next_p = temp_p;
   }

   Free_node(curr_p);

}

终端输出：

Stevens-MacBook-Air:CS220 Steven$ gcc -g -Wall -o linked_list_test linked_list_test.c
Stevens-MacBook-Air:CS220 Steven$ ./linked_list_test
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  h
while
here1
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  j
while
Segmentation fault: 11
Stevens-MacBook-Air:CS220 Steven$ ./linked_list_test
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  h
while
here1
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  j
while
Segmentation fault: 11
Stevens-MacBook-Air:CS220 Steven$ ./linked_list_test
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  b
while
here1
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  a
while
here2
Please enter a command (i, p, m, d, f, q):  ^C
Stevens-MacBook-Air:CS220 Steven$ gcc -g -Wall -o linked_list_test linked_list_test.c
Stevens-MacBook-Air:CS220 Steven$ ./linked_list_test
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  b
while
here1
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  c
while
here2
Please enter a command (i, p, m, d, f, q):  i
Please enter a value:  d
while
here3
Segmentation fault: 11