static int kvm_reboot(struct notifier_block *notifier, unsigned long val,
		      void *v)
{
	/*
	 * Some (well, at least mine) BIOSes hang on reboot if
	 * in vmx root mode.
	 *
	 * And Intel TXT required VMX off for all cpu when system shutdown.
	 */
	pr_info("kvm: exiting hardware virtualization\n");
	kvm_rebooting = true;
	on_each_cpu(hardware_disable_nolock, NULL, 1);
	return NOTIFY_OK;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.