static void smi_timeout(struct timer_list *t)
{
	struct smi_info   *smi_info = from_timer(smi_info, t, si_timer);
	enum si_sm_result smi_result;
	unsigned long     flags;
	unsigned long     jiffies_now;
	long              time_diff;
	long		  timeout;

	spin_lock_irqsave(&(smi_info->si_lock), flags);
	debug_timestamp("Timer");

	jiffies_now = jiffies;
	time_diff = (((long)jiffies_now - (long)smi_info->last_timeout_jiffies)
		     * SI_USEC_PER_JIFFY);
	smi_result = smi_event_handler(smi_info, time_diff);

	if ((smi_info->io.irq) && (!smi_info->interrupt_disabled)) {
		/* Running with interrupts, only do long timeouts. */
		timeout = jiffies + SI_TIMEOUT_JIFFIES;
		smi_inc_stat(smi_info, long_timeouts);
		goto do_mod_timer;
	}

	/*
	 * If the state machine asks for a short delay, then shorten
	 * the timer timeout.
	 */
	if (smi_result == SI_SM_CALL_WITH_DELAY) {
		smi_inc_stat(smi_info, short_timeouts);
		timeout = jiffies + 1;
	} else {
		smi_inc_stat(smi_info, long_timeouts);
		timeout = jiffies + SI_TIMEOUT_JIFFIES;
	}

do_mod_timer:
	if (smi_result != SI_SM_IDLE)
		smi_mod_timer(smi_info, timeout);
	else
		smi_info->timer_running = false;
	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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.