static void sender(void                *send_info,
		   struct ipmi_smi_msg *msg)
{
	struct smi_info   *smi_info = send_info;
	unsigned long     flags;

	debug_timestamp("Enqueue");

	if (smi_info->run_to_completion) {
		/*
		 * If we are running to completion, start it.  Upper
		 * layer will call flush_messages to clear it out.
		 */
		smi_info->waiting_msg = msg;
		return;
	}

	spin_lock_irqsave(&smi_info->si_lock, flags);
	/*
	 * The following two lines don't need to be under the lock for
	 * the lock's sake, but they do need SMP memory barriers to
	 * avoid getting things out of order.  We are already claiming
	 * the lock, anyway, so just do it under the lock to avoid the
	 * ordering problem.
	 */
	BUG_ON(smi_info->waiting_msg);
	smi_info->waiting_msg = msg;
	check_start_timer_thread(smi_info);
	spin_unlock_irqrestore(&smi_info->si_lock, flags);
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.