c
// ... (previous code)

n_coalesce = kmemdup(&new_coalesce, sizeof(new_coalesce), GFP_KERNEL);
if (!n_coalesce) {
    // Handle the error appropriately (e.g., log and return)
    // ...

    // IMPORTANT: Do not access new_coalesce.rules here
    return -ENOMEM; 
}

// ... (rest of the code) 
