io_port_init (void)
{
	unsigned long phys_iobase;

	/*
	 * Set `iobase' based on the EFI memory map or, failing that, the
	 * value firmware left in ar.k0.
	 *
	 * Note that in ia32 mode, IN/OUT instructions use ar.k0 to compute
	 * the port's virtual address, so ia32_load_state() loads it with a
	 * user virtual address.  But in ia64 mode, glibc uses the
	 * *physical* address in ar.k0 to mmap the appropriate area from
	 * /dev/mem, and the inX()/outX() interfaces use MMIO.  In both
	 * cases, user-mode can only use the legacy 0-64K I/O port space.
	 *
	 * ar.k0 is not involved in kernel I/O port accesses, which can use
	 * any of the I/O port spaces and are done via MMIO using the
	 * virtual mmio_base from the appropriate io_space[].
	 */
	phys_iobase = efi_get_iobase();
	if (!phys_iobase) {
		phys_iobase = ia64_get_kr(IA64_KR_IO_BASE);
		printk(KERN_INFO "No I/O port range found in EFI memory map, "
			"falling back to AR.KR0 (0x%lx)\n", phys_iobase);
	}
	ia64_iobase = (unsigned long) ioremap(phys_iobase, 0);
	ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));

	/* setup legacy IO port space */
	io_space[0].mmio_base = ia64_iobase;
	io_space[0].sparse = 1;
	num_io_spaces = 1;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.