Leetcode147c语言插入排序问题

Question

题目:Sort a linked list using insertion sort.(其实就是写一个直接插入排序)
但我的代码有问题，求大神指出错误在哪？

代码：

 /**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
 typedef struct listnode ListNode;
 struct listNode {
      int val;
      ListNode *next;
  };
struct ListNode* insertionSortList(struct ListNode* head) {

       if(head==NULL)
        return NULL;
    ListNode* newHead= (ListNode *)malloc(sizeof(ListNode));
    newHead->next=head;
    int i,j,tmp;

    for(ListNode* p=head->next,*prep=head;p;prep=p,p=p->next)
    {
        tmp=p1->val;
        p2=p1;
        for(ListNode *cur=newHead;cur->next!=p;cur=cur->next)
        {
            if（cur->next->val > p->val)
            {
                prep->next=p->next
                cur->next=p;
                p=prep;
                break;
            }


        }

    }
    ListNode* result = newHead->next;
    delete newHead;
    return result;
}