void nfs_writehdr_free(struct nfs_pgio_header *hdr)
{
	struct nfs_write_header *whdr = container_of(hdr, struct nfs_write_header, header);
	mempool_free(whdr, nfs_wdata_mempool);
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.