liquidio: fix for iq and droq cnts going negative

Hello Satanand Burla,

This is a semi-automatic email about new static checker warnings.

The patch cdb478e5e413: "liquidio: fix for iq and droq cnts going negative" from Jan 31, 2017, leads to the following Smatch complaint:

drivers/net/ethernet/cavium/liquidio/lio_main.c:2450 liquidio_napi_poll()
error: we previously assumed 'iq' could be null (see line 2436)

drivers/net/ethernet/cavium/liquidio/lio_main.c
2435 iq = oct->instr_queue[iq_no];

  2436		if (iq) {
                    ^^

Old code assumed "iq" can be NULL.

2437 /* Process iq buffers with in the budget limits */
2438 tx_done = octeon_flush_iq(oct, iq, budget);
2439 /* Update iq read-index rather than waiting for next interrupt.
2440 * Return back if tx_done is false.
2441 */
2442 update_txq_status(oct, iq_no);
2443 } else {
2444 dev_err(&oct->pci_dev->dev, "%s: iq (%d) num invalid\n",
2445 __func__, iq_no);
2446 }
2447
2448 /* force enable interrupt if reg cnts are high to avoid wraparound */
2449 if ((work_done < budget && tx_done) ||
2450 (iq->pkt_in_done >= MAX_REG_CNT) ||

                     ^^^^^^^^^^^^^^^

New code adds unchecked dereference.

  2451		    (droq->pkt_count >= MAX_REG_CNT)) {
  2452			tx_done = 1;

regards,
dan carpenter
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Also the other one in lio_vf_main.c

drivers/net/ethernet/cavium/liquidio/lio_vf_main.c:1635 liquidio_napi_poll()
error: we previously assumed 'iq' could be null (see line 1621)

regards,
dan carpenter

Quoted 9 lines · Dan Carpenter

Hello Satanand Burla,

This is a semi-automatic email about new static checker warnings.

The patch cdb478e5e413: "liquidio: fix for iq and droq cnts going negative" from Jan 31, 2017, leads to the following Smatch complaint:

drivers/net/ethernet/cavium/liquidio/lio_main.c:2450 liquidio_napi_poll()
error: we previously assumed 'iq' could be null (see line 2436)