[linux-next:master 2736/10638] 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)

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From: kernel test robot <lkp@intel.com>
To: kbuild@lists.01.org
Subject: [linux-next:master 2736/10638] 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)
Date: Fri, 27 Aug 2021 12:39:43 +0800	[thread overview]
Message-ID: <202108271237.qIqXe17x-lkp@intel.com> (raw)

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CC: kbuild-all(a)lists.01.org
CC: Linux Memory Management List <linux-mm@kvack.org>
TO: Stephane Grosjean <s.grosjean@peak-system.com>
CC: "Marc Kleine-Budde" <mkl@pengutronix.de>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   88fac11862d38306dd0d2398015744877140390d
commit: c11dcee758302702a83c6e85e4c4c3d9af42d2b3 [2736/10638] can: peak_usb: pcan_usb_decode_error(): upgrade handling of bus state changes
:::::: branch date: 
:::::: commit date: 5 weeks ago
config: i386-randconfig-m021-20210827 (attached as .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@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

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  449  
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);
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) {
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)) {
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;
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;
1c0ee046957648 Marc Kleine-Budde 2015-07-11  524  	netif_rx(skb);
46be265d338833 Stephane Grosjean 2012-03-02  525  
46be265d338833 Stephane Grosjean 2012-03-02  526  	return 0;
46be265d338833 Stephane Grosjean 2012-03-02  527  }
46be265d338833 Stephane Grosjean 2012-03-02  528  

:::::: The code at line 523 was first introduced by commit
:::::: c7b74967799b1af52b3045d69d4c26836b2d41de can: replace can_dlc as variable/element for payload length

:::::: TO: Oliver Hartkopp <socketcan@hartkopp.net>
:::::: CC: Marc Kleine-Budde <mkl@pengutronix.de>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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WARNING: multiple messages have this Message-ID (diff)

From: Dan Carpenter <dan.carpenter@oracle.com>
To: kbuild-all@lists.01.org
Subject: [linux-next:master 2736/10638] 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)
Date: Fri, 27 Aug 2021 11:05:05 +0300	[thread overview]
Message-ID: <202108271237.qIqXe17x-lkp@intel.com> (raw)

[-- Attachment #1: Type: text/plain, Size: 7190 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   88fac11862d38306dd0d2398015744877140390d
commit: c11dcee758302702a83c6e85e4c4c3d9af42d2b3 [2736/10638] can: peak_usb: pcan_usb_decode_error(): upgrade handling of bus state changes
config: i386-randconfig-m021-20210827 (attached as .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@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

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);
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;
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;
                                                                                      ^^^^^^^
Unchecked dereference.

1c0ee046957648 Marc Kleine-Budde 2015-07-11  524  	netif_rx(skb);
46be265d338833 Stephane Grosjean 2012-03-02  525  
46be265d338833 Stephane Grosjean 2012-03-02  526  	return 0;
46be265d338833 Stephane Grosjean 2012-03-02  527  }

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

next             reply	other threads:[~2021-08-27  4:39 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-27  4:39 kernel test robot [this message]
2021-08-27  8:05 ` [linux-next:master 2736/10638] 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) Dan Carpenter
2021-08-27  9:20 ` Marc Kleine-Budde
2021-08-27  9:54   ` Dan Carpenter
2021-08-27  9:54     ` Dan Carpenter

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