change this c code struct to dynamically(malloc)

So I created a c code for this data below

struct node {
    int value;
    struct node *next;
}

My code should dynamically create the structure given like this:

     1st -> 5 -> 7 -> 2, then 2->5(there is an arrow beneath 2 and link it back to 5)

Here is my code so far, do I need to change any pointer?

void insert(node * pointer, int value)
{
    node *start = pointer;

    /* Iterate through the list till we encounter the last node. */
    while (pointer->next != start)
    {
        pointer = pointer->next;
    }
    /* Allocate memory for the new node and put value in it. */
    pointer->next = (node *) malloc(sizeof(node));
    pointer = pointer->next;
    pointer->value = value;
    pointer->next = start;
}