static void handle_transaction_done(struct smi_info *smi_info)
{
	struct ipmi_smi_msg *msg;

	debug_timestamp("Done");
	switch (smi_info->si_state) {
	case SI_NORMAL:
		if (!smi_info->curr_msg)
			break;

		smi_info->curr_msg->rsp_size
			= smi_info->handlers->get_result(
				smi_info->si_sm,
				smi_info->curr_msg->rsp,
				IPMI_MAX_MSG_LENGTH);

		/*
		 * Do this here becase deliver_recv_msg() releases the
		 * lock, and a new message can be put in during the
		 * time the lock is released.
		 */
		msg = smi_info->curr_msg;
		smi_info->curr_msg = NULL;
		deliver_recv_msg(smi_info, msg);
		break;

	case SI_GETTING_FLAGS:
	{
		unsigned char msg[4];
		unsigned int  len;

		/* We got the flags from the SMI, now handle them. */
		len = smi_info->handlers->get_result(smi_info->si_sm, msg, 4);
		if (msg[2] != 0) {
			/* Error fetching flags, just give up for now. */
			smi_info->si_state = SI_NORMAL;
		} else if (len < 4) {
			/*
			 * Hmm, no flags.  That's technically illegal, but
			 * don't use uninitialized data.
			 */
			smi_info->si_state = SI_NORMAL;
		} else {
			smi_info->msg_flags = msg[3];
			handle_flags(smi_info);
		}
		break;
	}

	case SI_CLEARING_FLAGS:
	{
		unsigned char msg[3];

		/* We cleared the flags. */
		smi_info->handlers->get_result(smi_info->si_sm, msg, 3);
		if (msg[2] != 0) {
			/* Error clearing flags */
			dev_warn(smi_info->io.dev,
				 "Error clearing flags: %2.2x\n", msg[2]);
		}
		smi_info->si_state = SI_NORMAL;
		break;
	}

	case SI_GETTING_EVENTS:
	{
		smi_info->curr_msg->rsp_size
			= smi_info->handlers->get_result(
				smi_info->si_sm,
				smi_info->curr_msg->rsp,
				IPMI_MAX_MSG_LENGTH);

		/*
		 * Do this here becase deliver_recv_msg() releases the
		 * lock, and a new message can be put in during the
		 * time the lock is released.
		 */
		msg = smi_info->curr_msg;
		smi_info->curr_msg = NULL;
		if (msg->rsp[2] != 0) {
			/* Error getting event, probably done. */
			msg->done(msg);

			/* Take off the event flag. */
			smi_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
			handle_flags(smi_info);
		} else {
			smi_inc_stat(smi_info, events);

			/*
			 * Do this before we deliver the message
			 * because delivering the message releases the
			 * lock and something else can mess with the
			 * state.
			 */
			handle_flags(smi_info);

			deliver_recv_msg(smi_info, msg);
		}
		break;
	}

	case SI_GETTING_MESSAGES:
	{
		smi_info->curr_msg->rsp_size
			= smi_info->handlers->get_result(
				smi_info->si_sm,
				smi_info->curr_msg->rsp,
				IPMI_MAX_MSG_LENGTH);

		/*
		 * Do this here becase deliver_recv_msg() releases the
		 * lock, and a new message can be put in during the
		 * time the lock is released.
		 */
		msg = smi_info->curr_msg;
		smi_info->curr_msg = NULL;
		if (msg->rsp[2] != 0) {
			/* Error getting event, probably done. */
			msg->done(msg);

			/* Take off the msg flag. */
			smi_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
			handle_flags(smi_info);
		} else {
			smi_inc_stat(smi_info, incoming_messages);

			/*
			 * Do this before we deliver the message
			 * because delivering the message releases the
			 * lock and something else can mess with the
			 * state.
			 */
			handle_flags(smi_info);

			deliver_recv_msg(smi_info, msg);
		}
		break;
	}

	case SI_CHECKING_ENABLES:
	{
		unsigned char msg[4];
		u8 enables;
		bool irq_on;

		/* We got the flags from the SMI, now handle them. */
		smi_info->handlers->get_result(smi_info->si_sm, msg, 4);
		if (msg[2] != 0) {
			dev_warn(smi_info->io.dev,
				 "Couldn't get irq info: %x.\n", msg[2]);
			dev_warn(smi_info->io.dev,
				 "Maybe ok, but ipmi might run very slowly.\n");
			smi_info->si_state = SI_NORMAL;
			break;
		}
		enables = current_global_enables(smi_info, 0, &irq_on);
		if (smi_info->io.si_type == SI_BT)
			/* BT has its own interrupt enable bit. */
			check_bt_irq(smi_info, irq_on);
		if (enables != (msg[3] & GLOBAL_ENABLES_MASK)) {
			/* Enables are not correct, fix them. */
			msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
			msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
			msg[2] = enables | (msg[3] & ~GLOBAL_ENABLES_MASK);
			smi_info->handlers->start_transaction(
				smi_info->si_sm, msg, 3);
			smi_info->si_state = SI_SETTING_ENABLES;
		} else if (smi_info->supports_event_msg_buff) {
			smi_info->curr_msg = ipmi_alloc_smi_msg();
			if (!smi_info->curr_msg) {
				smi_info->si_state = SI_NORMAL;
				break;
			}
			start_getting_events(smi_info);
		} else {
			smi_info->si_state = SI_NORMAL;
		}
		break;
	}

	case SI_SETTING_ENABLES:
	{
		unsigned char msg[4];

		smi_info->handlers->get_result(smi_info->si_sm, msg, 4);
		if (msg[2] != 0)
			dev_warn(smi_info->io.dev,
				 "Could not set the global enables: 0x%x.\n",
				 msg[2]);

		if (smi_info->supports_event_msg_buff) {
			smi_info->curr_msg = ipmi_alloc_smi_msg();
			if (!smi_info->curr_msg) {
				smi_info->si_state = SI_NORMAL;
				break;
			}
			start_getting_events(smi_info);
		} else {
			smi_info->si_state = SI_NORMAL;
		}
		break;
	}
	}
}

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.