static void ion_buffer_remove_from_handle(struct ion_buffer *buffer)
{
	/*
	 * when a buffer is removed from a handle, if it is not in
	 * any other handles, copy the taskcomm and the pid of the
	 * process it's being removed from into the buffer.  At this
	 * point there will be no way to track what processes this buffer is
	 * being used by, it only exists as a dma_buf file descriptor.
	 * The taskcomm and pid can provide a debug hint as to where this fd
	 * is in the system
	 */
	mutex_lock(&buffer->lock);
	buffer->handle_count--;
	BUG_ON(buffer->handle_count < 0);
	if (!buffer->handle_count) {
		struct task_struct *task;

		task = current->group_leader;
		get_task_comm(buffer->task_comm, task);
		buffer->pid = task_pid_nr(task);
	}
	mutex_unlock(&buffer->lock);
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.