作为我在内核空间编写的程序的一部分，我创建了一个链接列表，其节点中有另一个链表 . 节点可以是两种类型，可以是仅具有int值和char *值的通道，也可以是具有int值和通道链接列表的设备文件 . 但是我的freeList函数中有NULL指针引用 .
我得到的错误是：无法处理内核NULL指针取消引用
知道如何解决这个问题吗？
struct node {
int val;
char* msg;
struct node* headOfIdList;
struct node* next;
};
static void addChannel(struct node* head, int id, char* msg) {
printk(KERN_INFO "creating channel\n");
struct node *curr ;
curr=head;
while (curr->next != NULL) {
curr = curr->next;
}
curr->next = kmalloc(sizeof(struct node), GFP_KERNEL);
curr->next->val = id;
curr->next->msg = msg;
curr->next->headOfIdList = NULL;
curr->next->next = NULL;
printk(KERN_INFO "channel created\n");
}
static void addFile(struct node* head, int minor) {
printk(KERN_INFO "creating file\n");
struct node *curr ;
curr=head;
while (curr->next != NULL) {
curr = curr->next;
}
curr->next = kmalloc(sizeof(struct node), GFP_KERNEL);
curr->next->val = minor;
curr->next->msg = NULL;
curr->next->headOfIdList = NULL;
curr->next->next = NULL;
printk(KERN_INFO "file created\n");
}
static struct node* find(struct node* head, int val) {
printk(KERN_INFO "looking for node\n");
struct node *curr ;
curr=head;
while (curr != NULL) {
if (curr->val == val) {
return curr;
}
curr = curr->next;
}
return NULL;
}
static void freeList(struct node* head) {
printk(KERN_INFO "freeing list\n");
struct node *curr ;
curr=head;
while (curr != NULL) {
struct node *tmp = curr->next;
if (curr->headOfIdList != NULL) {
freeList(curr->headOfIdList);
}
kfree(curr);
curr = tmp;
//curr=curr->next;
}
}
1 回答
如果你在循环外声明tmp var而while？
struct node *curr, *tmp;例如 .