Merge tag 'linux-can-fixes-for-6.13-20241202' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2024-12-02

The first patch is by me and allows the use of sleeping GPIOs to set
termination GPIOs.

Alexander Kozhinov fixes the gs_usb driver to use the endpoints
provided by the usb endpoint descriptions instead of hard coded ones.

Dario Binacchi contributes 11 statistics related patches for various
CAN driver. A potential use after free in the hi311x is fixed. The
statistics for the c_can, sun4i_can, hi311x, m_can, ifi_canfd,
sja1000, sun4i_can, ems_usb, f81604 are fixed: update statistics even
if the allocation of the error skb fails and fix the incrementing of
the rx,tx error counters.

A patch by me fixes the workaround for DS80000789E 6 erratum in the
mcp251xfd driver.

The last patch is by Dmitry Antipov, targets the j1939 CAN protocol
and fixes a skb reference counting issue.

* tag 'linux-can-fixes-for-6.13-20241202' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
  can: j1939: j1939_session_new(): fix skb reference counting
  can: mcp251xfd: mcp251xfd_get_tef_len(): work around erratum DS80000789E 6.
  can: f81604: f81604_handle_can_bus_errors(): fix {rx,tx}_errors statistics
  can: ems_usb: ems_usb_rx_err(): fix {rx,tx}_errors statistics
  can: sun4i_can: sun4i_can_err(): fix {rx,tx}_errors statistics
  can: sja1000: sja1000_err(): fix {rx,tx}_errors statistics
  can: hi311x: hi3110_can_ist(): fix {rx,tx}_errors statistics
  can: ifi_canfd: ifi_canfd_handle_lec_err(): fix {rx,tx}_errors statistics
  can: m_can: m_can_handle_lec_err(): fix {rx,tx}_errors statistics
  can: hi311x: hi3110_can_ist(): update state error statistics if skb allocation fails
  can: hi311x: hi3110_can_ist(): fix potential use-after-free
  can: sun4i_can: sun4i_can_err(): call can_change_state() even if cf is NULL
  can: c_can: c_can_handle_bus_err(): update statistics if skb allocation fails
  can: gs_usb: add usb endpoint address detection at driver probe step
  can: dev: can_set_termination(): allow sleeping GPIOs
====================

Link: https://patch.msgid.link/20241202090040.1110280-1-mkl@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

12 files changed, 253 insertions, 134 deletions

diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_can_main.c
index 511615dc3341..cc371d0c9f3c 100644
--- a/drivers/net/can/c_can/c_can_main.c
+++ b/drivers/net/can/c_can/c_can_main.c
@@ -1014,49 +1014,57 @@ static int c_can_handle_bus_err(struct net_device *dev,
 
 	/* propagate the error condition to the CAN stack */
 	skb = alloc_can_err_skb(dev, &cf);
-	if (unlikely(!skb))
-		return 0;
 
 	/* check for 'last error code' which tells us the
 	 * type of the last error to occur on the CAN bus
 	 */
-	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+	if (likely(skb))
+		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
 	switch (lec_type) {
 	case LEC_STUFF_ERROR:
 		netdev_dbg(dev, "stuff error\n");
-		cf->data[2] |= CAN_ERR_PROT_STUFF;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
 		stats->rx_errors++;
 		break;
 	case LEC_FORM_ERROR:
 		netdev_dbg(dev, "form error\n");
-		cf->data[2] |= CAN_ERR_PROT_FORM;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_FORM;
 		stats->rx_errors++;
 		break;
 	case LEC_ACK_ERROR:
 		netdev_dbg(dev, "ack error\n");
-		cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+		if (likely(skb))
+			cf->data[3] = CAN_ERR_PROT_LOC_ACK;
 		stats->tx_errors++;
 		break;
 	case LEC_BIT1_ERROR:
 		netdev_dbg(dev, "bit1 error\n");
-		cf->data[2] |= CAN_ERR_PROT_BIT1;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_BIT1;
 		stats->tx_errors++;
 		break;
 	case LEC_BIT0_ERROR:
 		netdev_dbg(dev, "bit0 error\n");
-		cf->data[2] |= CAN_ERR_PROT_BIT0;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_BIT0;
 		stats->tx_errors++;
 		break;
 	case LEC_CRC_ERROR:
 		netdev_dbg(dev, "CRC error\n");
-		cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+		if (likely(skb))
+			cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
 		stats->rx_errors++;
 		break;
 	default:
 		break;
 	}
 
+	if (unlikely(!skb))
+		return 0;
+
 	netif_receive_skb(skb);
 	return 1;
 }
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index 6792c14fd7eb..681643ab3780 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -468,7 +468,7 @@ static int can_set_termination(struct net_device *ndev, u16 term)
 	else
 		set = 0;
 
-	gpiod_set_value(priv->termination_gpio, set);
+	gpiod_set_value_cansleep(priv->termination_gpio, set);
 
 	return 0;
 }
diff --git a/drivers/net/can/ifi_canfd/ifi_canfd.c b/drivers/net/can/ifi_canfd/ifi_canfd.c
index d32b10900d2f..c86b57d47085 100644
--- a/drivers/net/can/ifi_canfd/ifi_canfd.c
+++ b/drivers/net/can/ifi_canfd/ifi_canfd.c
@@ -390,36 +390,55 @@ static int ifi_canfd_handle_lec_err(struct net_device *ndev)
 		return 0;
 
 	priv->can.can_stats.bus_error++;
-	stats->rx_errors++;
 
 	/* Propagate the error condition to the CAN stack. */
 	skb = alloc_can_err_skb(ndev, &cf);
-	if (unlikely(!skb))
-		return 0;
 
 	/* Read the error counter register and check for new errors. */
-	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+	if (likely(skb))
+		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
-	if (errctr & IFI_CANFD_ERROR_CTR_OVERLOAD_FIRST)
-		cf->data[2] |= CAN_ERR_PROT_OVERLOAD;
+	if (errctr & IFI_CANFD_ERROR_CTR_OVERLOAD_FIRST) {
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_OVERLOAD;
+	}
 
-	if (errctr & IFI_CANFD_ERROR_CTR_ACK_ERROR_FIRST)
-		cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+	if (errctr & IFI_CANFD_ERROR_CTR_ACK_ERROR_FIRST) {
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+	}
 
-	if (errctr & IFI_CANFD_ERROR_CTR_BIT0_ERROR_FIRST)
-		cf->data[2] |= CAN_ERR_PROT_BIT0;
+	if (errctr & IFI_CANFD_ERROR_CTR_BIT0_ERROR_FIRST) {
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_BIT0;
+	}
 
-	if (errctr & IFI_CANFD_ERROR_CTR_BIT1_ERROR_FIRST)
-		cf->data[2] |= CAN_ERR_PROT_BIT1;
+	if (errctr & IFI_CANFD_ERROR_CTR_BIT1_ERROR_FIRST) {
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_BIT1;
+	}
 
-	if (errctr & IFI_CANFD_ERROR_CTR_STUFF_ERROR_FIRST)
-		cf->data[2] |= CAN_ERR_PROT_STUFF;
+	if (errctr & IFI_CANFD_ERROR_CTR_STUFF_ERROR_FIRST) {
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
+	}
 
-	if (errctr & IFI_CANFD_ERROR_CTR_CRC_ERROR_FIRST)
-		cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+	if (errctr & IFI_CANFD_ERROR_CTR_CRC_ERROR_FIRST) {
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+	}
 
-	if (errctr & IFI_CANFD_ERROR_CTR_FORM_ERROR_FIRST)
-		cf->data[2] |= CAN_ERR_PROT_FORM;
+	if (errctr & IFI_CANFD_ERROR_CTR_FORM_ERROR_FIRST) {
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_FORM;
+	}
 
 	/* Reset the error counter, ack the IRQ and re-enable the counter. */
 	writel(IFI_CANFD_ERROR_CTR_ER_RESET, priv->base + IFI_CANFD_ERROR_CTR);
@@ -427,6 +446,9 @@ static int ifi_canfd_handle_lec_err(struct net_device *ndev)
 	       priv->base + IFI_CANFD_INTERRUPT);
 	writel(IFI_CANFD_ERROR_CTR_ER_ENABLE, priv->base + IFI_CANFD_ERROR_CTR);
 
+	if (unlikely(!skb))
+		return 0;
+
 	netif_receive_skb(skb);
 
 	return 1;
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 16e9e7d7527d..533bcb77c9f9 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -695,47 +695,60 @@ static int m_can_handle_lec_err(struct net_device *dev,
 	u32 timestamp = 0;
 
 	cdev->can.can_stats.bus_error++;
-	stats->rx_errors++;
 
 	/* propagate the error condition to the CAN stack */
 	skb = alloc_can_err_skb(dev, &cf);
-	if (unlikely(!skb))
-		return 0;
 
 	/* check for 'last error code' which tells us the
 	 * type of the last error to occur on the CAN bus
 	 */
-	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+	if (likely(skb))
+		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
 	switch (lec_type) {
 	case LEC_STUFF_ERROR:
 		netdev_dbg(dev, "stuff error\n");
-		cf->data[2] |= CAN_ERR_PROT_STUFF;
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
 		break;
 	case LEC_FORM_ERROR:
 		netdev_dbg(dev, "form error\n");
-		cf->data[2] |= CAN_ERR_PROT_FORM;
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_FORM;
 		break;
 	case LEC_ACK_ERROR:
 		netdev_dbg(dev, "ack error\n");
-		cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[3] = CAN_ERR_PROT_LOC_ACK;
 		break;
 	case LEC_BIT1_ERROR:
 		netdev_dbg(dev, "bit1 error\n");
-		cf->data[2] |= CAN_ERR_PROT_BIT1;
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_BIT1;
 		break;
 	case LEC_BIT0_ERROR:
 		netdev_dbg(dev, "bit0 error\n");
-		cf->data[2] |= CAN_ERR_PROT_BIT0;
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_BIT0;
 		break;
 	case LEC_CRC_ERROR:
 		netdev_dbg(dev, "CRC error\n");
-		cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
 		break;
 	default:
 		break;
 	}
 
+	if (unlikely(!skb))
+		return 0;
+
 	if (cdev->is_peripheral)
 		timestamp = m_can_get_timestamp(cdev);
 
diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index ddb3247948ad..4d245857ef1c 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -416,8 +416,6 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 	int ret = 0;
 
 	skb = alloc_can_err_skb(dev, &cf);
-	if (skb == NULL)
-		return -ENOMEM;
 
 	txerr = priv->read_reg(priv, SJA1000_TXERR);
 	rxerr = priv->read_reg(priv, SJA1000_RXERR);
@@ -425,8 +423,11 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 	if (isrc & IRQ_DOI) {
 		/* data overrun interrupt */
 		netdev_dbg(dev, "data overrun interrupt\n");
-		cf->can_id |= CAN_ERR_CRTL;
-		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		}
+
 		stats->rx_over_errors++;
 		stats->rx_errors++;
 		sja1000_write_cmdreg(priv, CMD_CDO);	/* clear bit */
@@ -452,7 +453,7 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 		else
 			state = CAN_STATE_ERROR_ACTIVE;
 	}
-	if (state != CAN_STATE_BUS_OFF) {
+	if (state != CAN_STATE_BUS_OFF && skb) {
 		cf->can_id |= CAN_ERR_CNT;
 		cf->data[6] = txerr;
 		cf->data[7] = rxerr;
@@ -460,33 +461,38 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 	if (isrc & IRQ_BEI) {
 		/* bus error interrupt */
 		priv->can.can_stats.bus_error++;
-		stats->rx_errors++;
 
 		ecc = priv->read_reg(priv, SJA1000_ECC);
+		if (skb) {
+			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
-		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
-
-		/* set error type */
-		switch (ecc & ECC_MASK) {
-		case ECC_BIT:
-			cf->data[2] |= CAN_ERR_PROT_BIT;
-			break;
-		case ECC_FORM:
-			cf->data[2] |= CAN_ERR_PROT_FORM;
-			break;
-		case ECC_STUFF:
-			cf->data[2] |= CAN_ERR_PROT_STUFF;
-			break;
-		default:
-			break;
-		}
+			/* set error type */
+			switch (ecc & ECC_MASK) {
+			case ECC_BIT:
+				cf->data[2] |= CAN_ERR_PROT_BIT;
+				break;
+			case ECC_FORM:
+				cf->data[2] |= CAN_ERR_PROT_FORM;
+				break;
+			case ECC_STUFF:
+				cf->data[2] |= CAN_ERR_PROT_STUFF;
+				break;
+			default:
+				break;
+			}
 
-		/* set error location */
-		cf->data[3] = ecc & ECC_SEG;
+			/* set error location */
+			cf->data[3] = ecc & ECC_SEG;
+		}
 
 		/* Error occurred during transmission? */
-		if ((ecc & ECC_DIR) == 0)
-			cf->data[2] |= CAN_ERR_PROT_TX;
+		if ((ecc & ECC_DIR) == 0) {
+			stats->tx_errors++;
+			if (skb)
+				cf->data[2] |= CAN_ERR_PROT_TX;
+		} else {
+			stats->rx_errors++;
+		}
 	}
 	if (isrc & IRQ_EPI) {
 		/* error passive interrupt */
@@ -502,8 +508,10 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 		netdev_dbg(dev, "arbitration lost interrupt\n");
 		alc = priv->read_reg(priv, SJA1000_ALC);
 		priv->can.can_stats.arbitration_lost++;
-		cf->can_id |= CAN_ERR_LOSTARB;
-		cf->data[0] = alc & 0x1f;
+		if (skb) {
+			cf->can_id |= CAN_ERR_LOSTARB;
+			cf->data[0] = alc & 0x1f;
+		}
 	}
 
 	if (state != priv->can.state) {
@@ -516,6 +524,9 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 			can_bus_off(dev);
 	}
 
+	if (!skb)
+		return -ENOMEM;
+
 	netif_rx(skb);
 
 	return ret;
diff --git a/drivers/net/can/spi/hi311x.c b/drivers/net/can/spi/hi311x.c
index 148d974ebb21..09ae218315d7 100644
--- a/drivers/net/can/spi/hi311x.c
+++ b/drivers/net/can/spi/hi311x.c
@@ -663,27 +663,27 @@ static irqreturn_t hi3110_can_ist(int irq, void *dev_id)
 			u8 rxerr, txerr;
 
 			skb = alloc_can_err_skb(net, &cf);
-			if (!skb)
-				break;
 
 			txerr = hi3110_read(spi, HI3110_READ_TEC);
 			rxerr = hi3110_read(spi, HI3110_READ_REC);
 			tx_state = txerr >= rxerr ? new_state : 0;
 			rx_state = txerr <= rxerr ? new_state : 0;
 			can_change_state(net, cf, tx_state, rx_state);
-			netif_rx(skb);
 
 			if (new_state == CAN_STATE_BUS_OFF) {
+				if (skb)
+					netif_rx(skb);
 				can_bus_off(net);
 				if (priv->can.restart_ms == 0) {
 					priv->force_quit = 1;
 					hi3110_hw_sleep(spi);
 					break;
 				}
-			} else {
+			} else if (skb) {
 				cf->can_id |= CAN_ERR_CNT;
 				cf->data[6] = txerr;
 				cf->data[7] = rxerr;
+				netif_rx(skb);
 			}
 		}
 
@@ -696,27 +696,38 @@ static irqreturn_t hi3110_can_ist(int irq, void *dev_id)
 			/* Check for protocol errors */
 			if (eflag & HI3110_ERR_PROTOCOL_MASK) {
 				skb = alloc_can_err_skb(net, &cf);
-				if (!skb)
-					break;
+				if (skb)
+					cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
-				cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 				priv->can.can_stats.bus_error++;
-				priv->net->stats.rx_errors++;
-				if (eflag & HI3110_ERR_BITERR)
-					cf->data[2] |= CAN_ERR_PROT_BIT;
-				else if (eflag & HI3110_ERR_FRMERR)
-					cf->data[2] |= CAN_ERR_PROT_FORM;
-				else if (eflag & HI3110_ERR_STUFERR)
-					cf->data[2] |= CAN_ERR_PROT_STUFF;
-				else if (eflag & HI3110_ERR_CRCERR)
-					cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
-				else if (eflag & HI3110_ERR_ACKERR)
-					cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
-
-				cf->data[6] = hi3110_read(spi, HI3110_READ_TEC);
-				cf->data[7] = hi3110_read(spi, HI3110_READ_REC);
+				if (eflag & HI3110_ERR_BITERR) {
+					priv->net->stats.tx_errors++;
+					if (skb)
+						cf->data[2] |= CAN_ERR_PROT_BIT;
+				} else if (eflag & HI3110_ERR_FRMERR) {
+					priv->net->stats.rx_errors++;
+					if (skb)
+						cf->data[2] |= CAN_ERR_PROT_FORM;
+				} else if (eflag & HI3110_ERR_STUFERR) {
+					priv->net->stats.rx_errors++;
+					if (skb)
+						cf->data[2] |= CAN_ERR_PROT_STUFF;
+				} else if (eflag & HI3110_ERR_CRCERR) {
+					priv->net->stats.rx_errors++;
+					if (skb)
+						cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
+				} else if (eflag & HI3110_ERR_ACKERR) {
+					priv->net->stats.tx_errors++;
+					if (skb)
+						cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
+				}
+
 				netdev_dbg(priv->net, "Bus Error\n");
-				netif_rx(skb);
+				if (skb) {
+					cf->data[6] = hi3110_read(spi, HI3110_READ_TEC);
+					cf->data[7] = hi3110_read(spi, HI3110_READ_REC);
+					netif_rx(skb);
+				}
 			}
 		}
 
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c
index d3ac865933fd..e94321849fd7 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c
@@ -21,6 +21,11 @@ static inline bool mcp251xfd_tx_fifo_sta_empty(u32 fifo_sta)
 	return fifo_sta & MCP251XFD_REG_FIFOSTA_TFERFFIF;
 }
 
+static inline bool mcp251xfd_tx_fifo_sta_less_than_half_full(u32 fifo_sta)
+{
+	return fifo_sta & MCP251XFD_REG_FIFOSTA_TFHRFHIF;
+}
+
 static inline int
 mcp251xfd_tef_tail_get_from_chip(const struct mcp251xfd_priv *priv,
 				 u8 *tef_tail)
@@ -147,7 +152,29 @@ mcp251xfd_get_tef_len(struct mcp251xfd_priv *priv, u8 *len_p)
 	BUILD_BUG_ON(sizeof(tx_ring->obj_num) != sizeof(len));
 
 	len = (chip_tx_tail << shift) - (tail << shift);
-	*len_p = len >> shift;
+	len >>= shift;
+
+	/* According to mcp2518fd erratum DS80000789E 6. the FIFOCI
+	 * bits of a FIFOSTA register, here the TX-FIFO tail index
+	 * might be corrupted.
+	 *
+	 * However here it seems the bit indicating that the TX-FIFO
+	 * is empty (MCP251XFD_REG_FIFOSTA_TFERFFIF) is not correct
+	 * while the TX-FIFO tail index is.
+	 *
+	 * We assume the TX-FIFO is empty, i.e. all pending CAN frames
+	 * haven been send, if:
+	 * - Chip's head and tail index are equal (len == 0).
+	 * - The TX-FIFO is less than half full.
+	 *   (The TX-FIFO empty case has already been checked at the
+	 *    beginning of this function.)
+	 * - No free buffers in the TX ring.
+	 */
+	if (len == 0 && mcp251xfd_tx_fifo_sta_less_than_half_full(fifo_sta) &&
+	    mcp251xfd_get_tx_free(tx_ring) == 0)
+		len = tx_ring->obj_num;
+
+	*len_p = len;
 
 	return 0;
 }
diff --git a/drivers/net/can/sun4i_can.c b/drivers/net/can/sun4i_can.c
index 360158c295d3..4311c1f0eafd 100644
--- a/drivers/net/can/sun4i_can.c
+++ b/drivers/net/can/sun4i_can.c
@@ -579,11 +579,9 @@ static int sun4i_can_err(struct net_device *dev, u8 isrc, u8 status)
 		/* bus error interrupt */
 		netdev_dbg(dev, "bus error interrupt\n");
 		priv->can.can_stats.bus_error++;
-		stats->rx_errors++;
+		ecc = readl(priv->base + SUN4I_REG_STA_ADDR);
 
 		if (likely(skb)) {
-			ecc = readl(priv->base + SUN4I_REG_STA_ADDR);
-
 			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
 			switch (ecc & SUN4I_STA_MASK_ERR) {
@@ -601,9 +599,15 @@ static int sun4i_can_err(struct net_device *dev, u8 isrc, u8 status)
 					       >> 16;
 				break;
 			}
-			/* error occurred during transmission? */
-			if ((ecc & SUN4I_STA_ERR_DIR) == 0)
+		}
+
+		/* error occurred during transmission? */
+		if ((ecc & SUN4I_STA_ERR_DIR) == 0) {
+			if (likely(skb))
 				cf->data[2] |= CAN_ERR_PROT_TX;
+			stats->tx_errors++;
+		} else {
+			stats->rx_errors++;
 		}
 	}
 	if (isrc & SUN4I_INT_ERR_PASSIVE) {
@@ -629,10 +633,10 @@ static int sun4i_can_err(struct net_device *dev, u8 isrc, u8 status)
 		tx_state = txerr >= rxerr ? state : 0;
 		rx_state = txerr <= rxerr ? state : 0;
 
-		if (likely(skb))
-			can_change_state(dev, cf, tx_state, rx_state);
-		else
-			priv->can.state = state;
+		/* The skb allocation might fail, but can_change_state()
+		 * handles cf == NULL.
+		 */
+		can_change_state(dev, cf, tx_state, rx_state);
 		if (state == CAN_STATE_BUS_OFF)
 			can_bus_off(dev);
 	}
diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index 050c0b49938a..5355bac4dccb 100644
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -335,15 +335,14 @@ static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 	struct net_device_stats *stats = &dev->netdev->stats;
 
 	skb = alloc_can_err_skb(dev->netdev, &cf);
-	if (skb == NULL)
-		return;
 
 	if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 		u8 state = msg->msg.can_state;
 
 		if (state & SJA1000_SR_BS) {
 			dev->can.state = CAN_STATE_BUS_OFF;
-			cf->can_id |= CAN_ERR_BUSOFF;
+			if (skb)
+				cf->can_id |= CAN_ERR_BUSOFF;
 
 			dev->can.can_stats.bus_off++;
 			can_bus_off(dev->netdev);
@@ -361,44 +360,53 @@ static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 
 		/* bus error interrupt */
 		dev->can.can_stats.bus_error++;
-		stats->rx_errors++;
 
-		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+		if (skb) {
+			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
-		switch (ecc & SJA1000_ECC_MASK) {
-		case SJA1000_ECC_BIT:
-			cf->data[2] |= CAN_ERR_PROT_BIT;
-			break;
-		case SJA1000_ECC_FORM:
-			cf->data[2] |= CAN_ERR_PROT_FORM;
-			break;
-		case SJA1000_ECC_STUFF:
-			cf->data[2] |= CAN_ERR_PROT_STUFF;
-			break;
-		default:
-			cf->data[3] = ecc & SJA1000_ECC_SEG;
-			break;
+			switch (ecc & SJA1000_ECC_MASK) {
+			case SJA1000_ECC_BIT:
+				cf->data[2] |= CAN_ERR_PROT_BIT;
+				break;
+			case SJA1000_ECC_FORM:
+				cf->data[2] |= CAN_ERR_PROT_FORM;
+				break;
+			case SJA1000_ECC_STUFF:
+				cf->data[2] |= CAN_ERR_PROT_STUFF;
+				break;
+			default:
+				cf->data[3] = ecc & SJA1000_ECC_SEG;
+				break;
+			}
 		}
 
 		/* Error occurred during transmission? */
-		if ((ecc & SJA1000_ECC_DIR) == 0)
-			cf->data[2] |= CAN_ERR_PROT_TX;
+		if ((ecc & SJA1000_ECC_DIR) == 0) {
+			stats->tx_errors++;
+			if (skb)
+				cf->data[2] |= CAN_ERR_PROT_TX;
+		} else {
+			stats->rx_errors++;
+		}
 
-		if (dev->can.state == CAN_STATE_ERROR_WARNING ||
-		    dev->can.state == CAN_STATE_ERROR_PASSIVE) {
+		if (skb && (dev->can.state == CAN_STATE_ERROR_WARNING ||
+			    dev->can.state == CAN_STATE_ERROR_PASSIVE)) {
 			cf->can_id |= CAN_ERR_CRTL;
 			cf->data[1] = (txerr > rxerr) ?
 			    CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 		}
 	} else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
-		cf->can_id |= CAN_ERR_CRTL;
-		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		}
 
 		stats->rx_over_errors++;
 		stats->rx_errors++;
 	}
 
-	netif_rx(skb);
+	if (skb)
+		netif_rx(skb);
 }
 
 /*
diff --git a/drivers/net/can/usb/f81604.c b/drivers/net/can/usb/f81604.c
index bc0c8903fe77..e0cfa1460b0b 100644
--- a/drivers/net/can/usb/f81604.c
+++ b/drivers/net/can/usb/f81604.c
@@ -526,7 +526,6 @@ static void f81604_handle_can_bus_errors(struct f81604_port_priv *priv,
 		netdev_dbg(netdev, "bus error interrupt\n");
 
 		priv->can.can_stats.bus_error++;
-		stats->rx_errors++;
 
 		if (skb) {
 			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
@@ -548,10 +547,15 @@ static void f81604_handle_can_bus_errors(struct f81604_port_priv *priv,
 
 			/* set error location */
 			cf->data[3] = data->ecc & F81604_SJA1000_ECC_SEG;
+		}
 
-			/* Error occurred during transmission? */
-			if ((data->ecc & F81604_SJA1000_ECC_DIR) == 0)
+		/* Error occurred during transmission? */
+		if ((data->ecc & F81604_SJA1000_ECC_DIR) == 0) {
+			stats->tx_errors++;
+			if (skb)
 				cf->data[2] |= CAN_ERR_PROT_TX;
+		} else {
+			stats->rx_errors++;
 		}
 
 		set_bit(F81604_CLEAR_ECC, &priv->clear_flags);
diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index bc86e9b329fd..b6f4de375df7 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -43,9 +43,6 @@
 #define USB_XYLANTA_SAINT3_VENDOR_ID 0x16d0
 #define USB_XYLANTA_SAINT3_PRODUCT_ID 0x0f30
 
-#define GS_USB_ENDPOINT_IN 1
-#define GS_USB_ENDPOINT_OUT 2
-
 /* Timestamp 32 bit timer runs at 1 MHz (1 µs tick). Worker accounts
  * for timer overflow (will be after ~71 minutes)
  */
@@ -336,6 +333,9 @@ struct gs_usb {
 
 	unsigned int hf_size_rx;
 	u8 active_channels;
+
+	unsigned int pipe_in;
+	unsigned int pipe_out;
 };
 
 /* 'allocate' a tx context.
@@ -687,7 +687,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 
 resubmit_urb:
 	usb_fill_bulk_urb(urb, parent->udev,
-			  usb_rcvbulkpipe(parent->udev, GS_USB_ENDPOINT_IN),
+			  parent->pipe_in,
 			  hf, dev->parent->hf_size_rx,
 			  gs_usb_receive_bulk_callback, parent);
 
@@ -819,7 +819,7 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
 	}
 
 	usb_fill_bulk_urb(urb, dev->udev,
-			  usb_sndbulkpipe(dev->udev, GS_USB_ENDPOINT_OUT),
+			  dev->parent->pipe_out,
 			  hf, dev->hf_size_tx,
 			  gs_usb_xmit_callback, txc);
 
@@ -925,8 +925,7 @@ static int gs_can_open(struct net_device *netdev)
 			/* fill, anchor, and submit rx urb */
 			usb_fill_bulk_urb(urb,
 					  dev->udev,
-					  usb_rcvbulkpipe(dev->udev,
-							  GS_USB_ENDPOINT_IN),
+					  dev->parent->pipe_in,
 					  buf,
 					  dev->parent->hf_size_rx,
 					  gs_usb_receive_bulk_callback, parent);
@@ -1413,6 +1412,7 @@ static int gs_usb_probe(struct usb_interface *intf,
 			const struct usb_device_id *id)
 {
 	struct usb_device *udev = interface_to_usbdev(intf);
+	struct usb_endpoint_descriptor *ep_in, *ep_out;
 	struct gs_host_frame *hf;
 	struct gs_usb *parent;
 	struct gs_host_config hconf = {
@@ -1422,6 +1422,13 @@ static int gs_usb_probe(struct usb_interface *intf,
 	unsigned int icount, i;
 	int rc;
 
+	rc = usb_find_common_endpoints(intf->cur_altsetting,
+				       &ep_in, &ep_out, NULL, NULL);
+	if (rc) {
+		dev_err(&intf->dev, "Required endpoints not found\n");
+		return rc;
+	}
+
 	/* send host config */
 	rc = usb_control_msg_send(udev, 0,
 				  GS_USB_BREQ_HOST_FORMAT,
@@ -1466,6 +1473,10 @@ static int gs_usb_probe(struct usb_interface *intf,
 	usb_set_intfdata(intf, parent);
 	parent->udev = udev;
 
+	/* store the detected endpoints */
+	parent->pipe_in = usb_rcvbulkpipe(parent->udev, ep_in->bEndpointAddress);
+	parent->pipe_out = usb_sndbulkpipe(parent->udev, ep_out->bEndpointAddress);
+
 	for (i = 0; i < icount; i++) {
 		unsigned int hf_size_rx = 0;
 
diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index 319f47df3330..95f7a7e65a73 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -1505,7 +1505,7 @@ static struct j1939_session *j1939_session_new(struct j1939_priv *priv,
 	session->state = J1939_SESSION_NEW;
 
 	skb_queue_head_init(&session->skb_queue);
-	skb_queue_tail(&session->skb_queue, skb);
+	skb_queue_tail(&session->skb_queue, skb_get(skb));
 
 	skcb = j1939_skb_to_cb(skb);
 	memcpy(&session->skcb, skcb, sizeof(session->skcb));