question about linked list

[corby]

i have this code for adding a node after the previous node, but valgrind is saying that there is a memory leak of 16 bytes, can someone please help me identify where the leak is? i think i didnt assign a null pointer somewhere but im not sure exactly where
struct Node *addAfter(struct List *list, struct Node *prevNode, void *data)
{
struct Node *temp;
temp = (struct Node *)malloc(sizeof(struct Node));
if (temp == NULL )
{
perror("malloc returned NULL");
return NULL;
}else
{
temp->data = data;
if(prevNode == NULL)
{
prevNode = addFront(list, temp->data);
prevNode->next = NULL;
}else
{
while(prevNode->next != NULL)
{
prevNode = prevNode->next;
}

temp->next = NULL;
prevNode->next = temp;
}

return prevNode;
}
};