On 03.12.2021 17:09:55, Dan Carpenter wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > head: 58e1100fdc5990b0cc0d4beaf2562a92e621ac7d > commit: c11dcee758302702a83c6e85e4c4c3d9af42d2b3 can: peak_usb: pcan_usb_decode_error(): upgrade handling of bus state changes > config: x86_64-randconfig-m001-20211202 (https://download.01.org/0day-ci/archive/20211202/202112021833.wABxM5UN-lkp@xxxxxxxxx/config) > compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > > smatch warnings: > drivers/net/can/usb/peak_usb/pcan_usb.c:523 pcan_usb_decode_error() error: we previously assumed 'cf' could be null (see line 503) > > vim +/cf +523 drivers/net/can/usb/peak_usb/pcan_usb.c > > 46be265d338833 Stephane Grosjean 2012-03-02 450 static int pcan_usb_decode_error(struct pcan_usb_msg_context *mc, u8 n, > 46be265d338833 Stephane Grosjean 2012-03-02 451 u8 status_len) > 46be265d338833 Stephane Grosjean 2012-03-02 452 { > 46be265d338833 Stephane Grosjean 2012-03-02 453 struct sk_buff *skb; > 46be265d338833 Stephane Grosjean 2012-03-02 454 struct can_frame *cf; > c11dcee7583027 Stephane Grosjean 2021-07-15 455 enum can_state new_state = CAN_STATE_ERROR_ACTIVE; > 46be265d338833 Stephane Grosjean 2012-03-02 456 > 46be265d338833 Stephane Grosjean 2012-03-02 457 /* ignore this error until 1st ts received */ > 46be265d338833 Stephane Grosjean 2012-03-02 458 if (n == PCAN_USB_ERROR_QOVR) > 46be265d338833 Stephane Grosjean 2012-03-02 459 if (!mc->pdev->time_ref.tick_count) > 46be265d338833 Stephane Grosjean 2012-03-02 460 return 0; > 46be265d338833 Stephane Grosjean 2012-03-02 461 > c11dcee7583027 Stephane Grosjean 2021-07-15 462 /* allocate an skb to store the error frame */ > c11dcee7583027 Stephane Grosjean 2021-07-15 463 skb = alloc_can_err_skb(mc->netdev, &cf); alloc_can_err_skb() -> alloc_canfd_skb() https://elixir.bootlin.com/linux/v5.15/source/drivers/net/can/dev/skb.c#L210 If skb is NULL, cf is set to NULL, too. > 46be265d338833 Stephane Grosjean 2012-03-02 464 > c11dcee7583027 Stephane Grosjean 2021-07-15 465 if (n & PCAN_USB_ERROR_RXQOVR) { > c11dcee7583027 Stephane Grosjean 2021-07-15 466 /* data overrun interrupt */ > c11dcee7583027 Stephane Grosjean 2021-07-15 467 netdev_dbg(mc->netdev, "data overrun interrupt\n"); > c11dcee7583027 Stephane Grosjean 2021-07-15 468 mc->netdev->stats.rx_over_errors++; > c11dcee7583027 Stephane Grosjean 2021-07-15 469 mc->netdev->stats.rx_errors++; > c11dcee7583027 Stephane Grosjean 2021-07-15 470 if (cf) { > > Check for NULL > > c11dcee7583027 Stephane Grosjean 2021-07-15 471 cf->can_id |= CAN_ERR_CRTL; > c11dcee7583027 Stephane Grosjean 2021-07-15 472 cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW; > 46be265d338833 Stephane Grosjean 2012-03-02 473 } > 46be265d338833 Stephane Grosjean 2012-03-02 474 } > 46be265d338833 Stephane Grosjean 2012-03-02 475 > c11dcee7583027 Stephane Grosjean 2021-07-15 476 if (n & PCAN_USB_ERROR_TXQFULL) > c11dcee7583027 Stephane Grosjean 2021-07-15 477 netdev_dbg(mc->netdev, "device Tx queue full)\n"); > c11dcee7583027 Stephane Grosjean 2021-07-15 478 > 46be265d338833 Stephane Grosjean 2012-03-02 479 if (n & PCAN_USB_ERROR_BUS_OFF) { > 46be265d338833 Stephane Grosjean 2012-03-02 480 new_state = CAN_STATE_BUS_OFF; > c11dcee7583027 Stephane Grosjean 2021-07-15 481 } else if (n & PCAN_USB_ERROR_BUS_HEAVY) { > c11dcee7583027 Stephane Grosjean 2021-07-15 482 new_state = ((mc->pdev->bec.txerr >= 128) || > c11dcee7583027 Stephane Grosjean 2021-07-15 483 (mc->pdev->bec.rxerr >= 128)) ? > c11dcee7583027 Stephane Grosjean 2021-07-15 484 CAN_STATE_ERROR_PASSIVE : > c11dcee7583027 Stephane Grosjean 2021-07-15 485 CAN_STATE_ERROR_WARNING; > c11dcee7583027 Stephane Grosjean 2021-07-15 486 } else { > c11dcee7583027 Stephane Grosjean 2021-07-15 487 new_state = CAN_STATE_ERROR_ACTIVE; > 46be265d338833 Stephane Grosjean 2012-03-02 488 } > 46be265d338833 Stephane Grosjean 2012-03-02 489 > c11dcee7583027 Stephane Grosjean 2021-07-15 490 /* handle change of state */ > c11dcee7583027 Stephane Grosjean 2021-07-15 491 if (new_state != mc->pdev->dev.can.state) { > c11dcee7583027 Stephane Grosjean 2021-07-15 492 enum can_state tx_state = > c11dcee7583027 Stephane Grosjean 2021-07-15 493 (mc->pdev->bec.txerr >= mc->pdev->bec.rxerr) ? > c11dcee7583027 Stephane Grosjean 2021-07-15 494 new_state : 0; > c11dcee7583027 Stephane Grosjean 2021-07-15 495 enum can_state rx_state = > c11dcee7583027 Stephane Grosjean 2021-07-15 496 (mc->pdev->bec.txerr <= mc->pdev->bec.rxerr) ? > c11dcee7583027 Stephane Grosjean 2021-07-15 497 new_state : 0; > 46be265d338833 Stephane Grosjean 2012-03-02 498 > c11dcee7583027 Stephane Grosjean 2021-07-15 499 can_change_state(mc->netdev, cf, tx_state, rx_state); > 46be265d338833 Stephane Grosjean 2012-03-02 500 > c11dcee7583027 Stephane Grosjean 2021-07-15 501 if (new_state == CAN_STATE_BUS_OFF) { > 46be265d338833 Stephane Grosjean 2012-03-02 502 can_bus_off(mc->netdev); > c11dcee7583027 Stephane Grosjean 2021-07-15 @503 } else if (cf && (cf->can_id & CAN_ERR_CRTL)) { > > Check for NULL > > c11dcee7583027 Stephane Grosjean 2021-07-15 504 /* Supply TX/RX error counters in case of > c11dcee7583027 Stephane Grosjean 2021-07-15 505 * controller error. > c11dcee7583027 Stephane Grosjean 2021-07-15 506 */ > ea8b33bde76c8f Stephane Grosjean 2019-12-06 507 cf->data[6] = mc->pdev->bec.txerr; > ea8b33bde76c8f Stephane Grosjean 2019-12-06 508 cf->data[7] = mc->pdev->bec.rxerr; > ea8b33bde76c8f Stephane Grosjean 2019-12-06 509 } > 46be265d338833 Stephane Grosjean 2012-03-02 510 } > 46be265d338833 Stephane Grosjean 2012-03-02 511 > c11dcee7583027 Stephane Grosjean 2021-07-15 512 if (!skb) > c11dcee7583027 Stephane Grosjean 2021-07-15 513 return -ENOMEM; If cf is NULL, so is skb.... > 46be265d338833 Stephane Grosjean 2012-03-02 514 > 46be265d338833 Stephane Grosjean 2012-03-02 515 if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) { > c9faaa09e2a133 Oliver Hartkopp 2012-11-21 516 struct skb_shared_hwtstamps *hwts = skb_hwtstamps(skb); > c9faaa09e2a133 Oliver Hartkopp 2012-11-21 517 > d5888a1e75c799 Arnd Bergmann 2017-11-03 518 peak_usb_get_ts_time(&mc->pdev->time_ref, mc->ts16, > d5888a1e75c799 Arnd Bergmann 2017-11-03 519 &hwts->hwtstamp); > 46be265d338833 Stephane Grosjean 2012-03-02 520 } > 46be265d338833 Stephane Grosjean 2012-03-02 521 > 46be265d338833 Stephane Grosjean 2012-03-02 522 mc->netdev->stats.rx_packets++; > c7b74967799b1a Oliver Hartkopp 2020-11-20 @523 mc->netdev->stats.rx_bytes += cf->len; > ^^^^^^^^ > No check for NULL. ...then this code is not reached. Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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