Merge tag 'linux-can-fixes-for-6.10-20240621' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2024-06-21

The first patch is by Oleksij Rempel, it enhances the error handling
for tightly received RTS message in the j1939 protocol.

Shigeru Yoshida's patch fixes a kernel information leak in
j1939_send_one() in the j1939 protocol.

Followed by a patch by Oleksij Rempel for the j1939 protocol, to
properly recover from a CAN bus error during BAM transmission.

A patch by Chen Ni properly propagates errors in the kvaser_usb
driver.

The last patch is by Vitor Soares, that fixes an infinite loop in the
mcp251xfd driver is SPI async sending fails during xmit.

* tag 'linux-can-fixes-for-6.10-20240621' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
  can: mcp251xfd: fix infinite loop when xmit fails
  can: kvaser_usb: fix return value for hif_usb_send_regout
  net: can: j1939: recover socket queue on CAN bus error during BAM transmission
  net: can: j1939: Initialize unused data in j1939_send_one()
  net: can: j1939: enhanced error handling for tightly received RTS messages in xtp_rx_rts_session_new
====================

Link: https://patch.msgid.link/20240621121739.434355-1-mkl@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 20 insertions, 7 deletions

diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
index a6fb89fa6278..7e8a20f2fc42 100644
--- a/net/can/j1939/main.c
+++ b/net/can/j1939/main.c
@@ -30,10 +30,6 @@ MODULE_ALIAS("can-proto-" __stringify(CAN_J1939));
 /* CAN_HDR: #bytes before can_frame data part */
 #define J1939_CAN_HDR (offsetof(struct can_frame, data))
 
-/* CAN_FTR: #bytes beyond data part */
-#define J1939_CAN_FTR (sizeof(struct can_frame) - J1939_CAN_HDR - \
-		 sizeof(((struct can_frame *)0)->data))
-
 /* lowest layer */
 static void j1939_can_recv(struct sk_buff *iskb, void *data)
 {
@@ -342,7 +338,7 @@ int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb)
 	memset(cf, 0, J1939_CAN_HDR);
 
 	/* make it a full can frame again */
-	skb_put(skb, J1939_CAN_FTR + (8 - dlc));
+	skb_put_zero(skb, 8 - dlc);
 
 	canid = CAN_EFF_FLAG |
 		(skcb->priority << 26) |
diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index fe3df23a2595..4be73de5033c 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -1593,8 +1593,8 @@ j1939_session *j1939_xtp_rx_rts_session_new(struct j1939_priv *priv,
 	struct j1939_sk_buff_cb skcb = *j1939_skb_to_cb(skb);
 	struct j1939_session *session;
 	const u8 *dat;
+	int len, ret;
 	pgn_t pgn;
-	int len;
 
 	netdev_dbg(priv->ndev, "%s\n", __func__);
 
@@ -1653,7 +1653,22 @@ j1939_session *j1939_xtp_rx_rts_session_new(struct j1939_priv *priv,
 	session->tskey = priv->rx_tskey++;
 	j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_RTS);
 
-	WARN_ON_ONCE(j1939_session_activate(session));
+	ret = j1939_session_activate(session);
+	if (ret) {
+		/* Entering this scope indicates an issue with the J1939 bus.
+		 * Possible scenarios include:
+		 * - A time lapse occurred, and a new session was initiated
+		 *   due to another packet being sent correctly. This could
+		 *   have been caused by too long interrupt, debugger, or being
+		 *   out-scheduled by another task.
+		 * - The bus is receiving numerous erroneous packets, either
+		 *   from a malfunctioning device or during a test scenario.
+		 */
+		netdev_alert(priv->ndev, "%s: 0x%p: concurrent session with same addr (%02x %02x) is already active.\n",
+			     __func__, session, skcb.addr.sa, skcb.addr.da);
+		j1939_session_put(session);
+		return NULL;
+	}
 
 	return session;
 }
@@ -1681,6 +1696,8 @@ static int j1939_xtp_rx_rts_session_active(struct j1939_session *session,
 
 		j1939_session_timers_cancel(session);
 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
+		if (session->transmission)
+			j1939_session_deactivate_activate_next(session);
 
 		return -EBUSY;
 	}