Hello Johan Hovold,
The patch 20777bc57c34: "NFC: fix broken device allocation" from Mar
30, 2017, leads to the following static checker warning:
drivers/nfc/pn533/pn533.c:2653 pn533_register_device()
error: 'priv->nfc_dev' dereferencing possible ERR_PTR()
drivers/nfc/pn533/pn533.c
2639 skb_queue_head_init(&priv->resp_q);
2640 skb_queue_head_init(&priv->fragment_skb);
2641
2642 INIT_LIST_HEAD(&priv->cmd_queue);
2643
2644 priv->nfc_dev = nfc_allocate_device(&pn533_nfc_ops, protocols,
2645 priv->ops->tx_header_len +
2646 PN533_CMD_DATAEXCH_HEAD_LEN,
2647 priv->ops->tx_tail_len);
We changed this to return error pointers as well as NULL. When
functions return a NULL as well as error pointers, then NULL is supposed
to be a special case of success but here it's just a failure. That's
messy and bug prone.
2648 if (!priv->nfc_dev) {
2649 rc = -ENOMEM;
2650 goto destroy_wq;
2651 }
2652
2653 nfc_set_parent_dev(priv->nfc_dev, parent);
^^^^^^^^^^^^^
Oops.
2654 nfc_set_drvdata(priv->nfc_dev, priv);
2655
2656 rc = nfc_register_device(priv->nfc_dev);
2657 if (rc)
2658 goto free_nfc_dev;
regards,
dan carpenter
