void smb2_reconnect_server(struct work_struct *work)
{
	struct TCP_Server_Info *server = container_of(work,
					struct TCP_Server_Info, reconnect.work);
	struct cifs_ses *ses;
	struct cifs_tcon *tcon, *tcon2;
	struct list_head tmp_list;
	int tcon_exist = false;
	int rc;
	int resched = false;


	/* Prevent simultaneous reconnects that can corrupt tcon->rlist list */
	mutex_lock(&server->reconnect_mutex);

	INIT_LIST_HEAD(&tmp_list);
	cifs_dbg(FYI, "Need negotiate, reconnecting tcons\n");

	spin_lock(&cifs_tcp_ses_lock);
	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
			if (tcon->need_reconnect || tcon->need_reopen_files) {
				tcon->tc_count++;
				list_add_tail(&tcon->rlist, &tmp_list);
				tcon_exist = true;
			}
		}
		if (ses->tcon_ipc && ses->tcon_ipc->need_reconnect) {
			list_add_tail(&ses->tcon_ipc->rlist, &tmp_list);
			tcon_exist = true;
		}
	}
	/*
	 * Get the reference to server struct to be sure that the last call of
	 * cifs_put_tcon() in the loop below won't release the server pointer.
	 */
	if (tcon_exist)
		server->srv_count++;

	spin_unlock(&cifs_tcp_ses_lock);

	list_for_each_entry_safe(tcon, tcon2, &tmp_list, rlist) {
		rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon);
		if (!rc)
			cifs_reopen_persistent_handles(tcon);
		else
			resched = true;
		list_del_init(&tcon->rlist);
		cifs_put_tcon(tcon);
	}

	cifs_dbg(FYI, "Reconnecting tcons finished\n");
	if (resched)
		queue_delayed_work(cifsiod_wq, &server->reconnect, 2 * HZ);
	mutex_unlock(&server->reconnect_mutex);

	/* now we can safely release srv struct */
	if (tcon_exist)
		cifs_put_tcp_session(server, 1);
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.