From 641427d5bf90af0625081bf27555418b101274cd Mon Sep 17 00:00:00 2001 From: Alex Tran Date: Wed, 3 Sep 2025 20:17:09 -0700 Subject: [PATCH 1/7] docs: networking: can: change bcm_msg_head frames member to support flexible array The documentation of the 'bcm_msg_head' struct does not match how it is defined in 'bcm.h'. Changed the frames member to a flexible array, matching the definition in the header file. See commit 94dfc73e7cf4 ("treewide: uapi: Replace zero-length arrays with flexible-array members") Signed-off-by: Alex Tran Acked-by: Oliver Hartkopp Link: https://patch.msgid.link/20250904031709.1426895-1-alex.t.tran@gmail.com Fixes: 94dfc73e7cf4 ("treewide: uapi: Replace zero-length arrays with flexible-array members") Link: https://bugzilla.kernel.org/show_bug.cgi?id=217783 Signed-off-by: Marc Kleine-Budde --- Documentation/networking/can.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst index bc1b585355f7..7650c4b5be5f 100644 --- a/Documentation/networking/can.rst +++ b/Documentation/networking/can.rst @@ -742,7 +742,7 @@ The broadcast manager sends responses to user space in the same form: struct timeval ival1, ival2; /* count and subsequent interval */ canid_t can_id; /* unique can_id for task */ __u32 nframes; /* number of can_frames following */ - struct can_frame frames[0]; + struct can_frame frames[]; }; The aligned payload 'frames' uses the same basic CAN frame structure defined From d013ebc3499fd87cb9dee1dafd0c58aeb05c27c1 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Wed, 10 Sep 2025 16:56:06 +0200 Subject: [PATCH 2/7] selftests: can: enable CONFIG_CAN_VCAN as a module A proper kernel configuration for running kselftest can be obtained with: $ yes | make kselftest-merge Build of 'vcan' driver is currently missing, while the other required knobs are already there because of net/link_netns.py [1]. Add a config file in selftests/net/can to store the minimum set of kconfig needed for CAN selftests. [1] https://patch.msgid.link/20250219125039.18024-14-shaw.leon@gmail.com Fixes: 77442ffa83e8 ("selftests: can: Import tst-filter from can-tests") Reviewed-by: Vincent Mailhol Signed-off-by: Davide Caratti Link: https://patch.msgid.link/fa4c0ea262ec529f25e5f5aa9269d84764c67321.1757516009.git.dcaratti@redhat.com Signed-off-by: Marc Kleine-Budde --- tools/testing/selftests/net/can/config | 3 +++ 1 file changed, 3 insertions(+) create mode 100644 tools/testing/selftests/net/can/config diff --git a/tools/testing/selftests/net/can/config b/tools/testing/selftests/net/can/config new file mode 100644 index 000000000000..188f79796670 --- /dev/null +++ b/tools/testing/selftests/net/can/config @@ -0,0 +1,3 @@ +CONFIG_CAN=m +CONFIG_CAN_DEV=m +CONFIG_CAN_VCAN=m From 7fcbe5b2c6a4b5407bf2241fdb71e0a390f6ab9a Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Mon, 25 Aug 2025 23:07:24 +0900 Subject: [PATCH 3/7] can: j1939: implement NETDEV_UNREGISTER notification handler syzbot is reporting unregister_netdevice: waiting for vcan0 to become free. Usage count = 2 problem, for j1939 protocol did not have NETDEV_UNREGISTER notification handler for undoing changes made by j1939_sk_bind(). Commit 25fe97cb7620 ("can: j1939: move j1939_priv_put() into sk_destruct callback") expects that a call to j1939_priv_put() can be unconditionally delayed until j1939_sk_sock_destruct() is called. But we need to call j1939_priv_put() against an extra ref held by j1939_sk_bind() call (as a part of undoing changes made by j1939_sk_bind()) as soon as NETDEV_UNREGISTER notification fires (i.e. before j1939_sk_sock_destruct() is called via j1939_sk_release()). Otherwise, the extra ref on "struct j1939_priv" held by j1939_sk_bind() call prevents "struct net_device" from dropping the usage count to 1; making it impossible for unregister_netdevice() to continue. Reported-by: syzbot Closes: https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84 Tested-by: syzbot Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Fixes: 25fe97cb7620 ("can: j1939: move j1939_priv_put() into sk_destruct callback") Signed-off-by: Tetsuo Handa Tested-by: Oleksij Rempel Acked-by: Oleksij Rempel Link: https://patch.msgid.link/ac9db9a4-6c30-416e-8b94-96e6559d55b2@I-love.SAKURA.ne.jp [mkl: remove space in front of label] Signed-off-by: Marc Kleine-Budde --- net/can/j1939/j1939-priv.h | 1 + net/can/j1939/main.c | 3 +++ net/can/j1939/socket.c | 49 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 53 insertions(+) diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h index 31a93cae5111..81f58924b4ac 100644 --- a/net/can/j1939/j1939-priv.h +++ b/net/can/j1939/j1939-priv.h @@ -212,6 +212,7 @@ void j1939_priv_get(struct j1939_priv *priv); /* notify/alert all j1939 sockets bound to ifindex */ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv); +void j1939_sk_netdev_event_unregister(struct j1939_priv *priv); int j1939_cancel_active_session(struct j1939_priv *priv, struct sock *sk); void j1939_tp_init(struct j1939_priv *priv); diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c index 7e8a20f2fc42..3706a872ecaf 100644 --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -377,6 +377,9 @@ static int j1939_netdev_notify(struct notifier_block *nb, j1939_sk_netdev_event_netdown(priv); j1939_ecu_unmap_all(priv); break; + case NETDEV_UNREGISTER: + j1939_sk_netdev_event_unregister(priv); + break; } j1939_priv_put(priv); diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index 3d8b588822f9..70ebc861ea2a 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -1300,6 +1300,55 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv) read_unlock_bh(&priv->j1939_socks_lock); } +void j1939_sk_netdev_event_unregister(struct j1939_priv *priv) +{ + struct sock *sk; + struct j1939_sock *jsk; + bool wait_rcu = false; + +rescan: /* The caller is holding a ref on this "priv" via j1939_priv_get_by_ndev(). */ + read_lock_bh(&priv->j1939_socks_lock); + list_for_each_entry(jsk, &priv->j1939_socks, list) { + /* Skip if j1939_jsk_add() is not called on this socket. */ + if (!(jsk->state & J1939_SOCK_BOUND)) + continue; + sk = &jsk->sk; + sock_hold(sk); + read_unlock_bh(&priv->j1939_socks_lock); + /* Check if j1939_jsk_del() is not yet called on this socket after holding + * socket's lock, for both j1939_sk_bind() and j1939_sk_release() call + * j1939_jsk_del() with socket's lock held. + */ + lock_sock(sk); + if (jsk->state & J1939_SOCK_BOUND) { + /* Neither j1939_sk_bind() nor j1939_sk_release() called j1939_jsk_del(). + * Make this socket no longer bound, by pretending as if j1939_sk_bind() + * dropped old references but did not get new references. + */ + j1939_jsk_del(priv, jsk); + j1939_local_ecu_put(priv, jsk->addr.src_name, jsk->addr.sa); + j1939_netdev_stop(priv); + /* Call j1939_priv_put() now and prevent j1939_sk_sock_destruct() from + * calling the corresponding j1939_priv_put(). + * + * j1939_sk_sock_destruct() is supposed to call j1939_priv_put() after + * an RCU grace period. But since the caller is holding a ref on this + * "priv", we can defer synchronize_rcu() until immediately before + * the caller calls j1939_priv_put(). + */ + j1939_priv_put(priv); + jsk->priv = NULL; + wait_rcu = true; + } + release_sock(sk); + sock_put(sk); + goto rescan; + } + read_unlock_bh(&priv->j1939_socks_lock); + if (wait_rcu) + synchronize_rcu(); +} + static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd, unsigned long arg) { From f214744c8a27c3c1da6b538c232da22cd027530e Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Sun, 24 Aug 2025 19:30:09 +0900 Subject: [PATCH 4/7] can: j1939: j1939_sk_bind(): call j1939_priv_put() immediately when j1939_local_ecu_get() failed Commit 25fe97cb7620 ("can: j1939: move j1939_priv_put() into sk_destruct callback") expects that a call to j1939_priv_put() can be unconditionally delayed until j1939_sk_sock_destruct() is called. But a refcount leak will happen when j1939_sk_bind() is called again after j1939_local_ecu_get() from previous j1939_sk_bind() call returned an error. We need to call j1939_priv_put() before j1939_sk_bind() returns an error. Fixes: 25fe97cb7620 ("can: j1939: move j1939_priv_put() into sk_destruct callback") Signed-off-by: Tetsuo Handa Tested-by: Oleksij Rempel Acked-by: Oleksij Rempel Link: https://patch.msgid.link/4f49a1bc-a528-42ad-86c0-187268ab6535@I-love.SAKURA.ne.jp Signed-off-by: Marc Kleine-Budde --- net/can/j1939/socket.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index 70ebc861ea2a..88e7160d4248 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -521,6 +521,9 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len) ret = j1939_local_ecu_get(priv, jsk->addr.src_name, jsk->addr.sa); if (ret) { j1939_netdev_stop(priv); + jsk->priv = NULL; + synchronize_rcu(); + j1939_priv_put(priv); goto out_release_sock; } From 06e02da29f6f1a45fc07bd60c7eaf172dc21e334 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Sun, 24 Aug 2025 19:27:40 +0900 Subject: [PATCH 5/7] can: j1939: j1939_local_ecu_get(): undo increment when j1939_local_ecu_get() fails Since j1939_sk_bind() and j1939_sk_release() call j1939_local_ecu_put() when J1939_SOCK_BOUND was already set, but the error handling path for j1939_sk_bind() will not set J1939_SOCK_BOUND when j1939_local_ecu_get() fails, j1939_local_ecu_get() needs to undo priv->ents[sa].nusers++ when j1939_local_ecu_get() returns an error. Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Signed-off-by: Tetsuo Handa Tested-by: Oleksij Rempel Acked-by: Oleksij Rempel Link: https://patch.msgid.link/e7f80046-4ff7-4ce2-8ad8-7c3c678a42c9@I-love.SAKURA.ne.jp Signed-off-by: Marc Kleine-Budde --- net/can/j1939/bus.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/can/j1939/bus.c b/net/can/j1939/bus.c index 39844f14eed8..797719cb227e 100644 --- a/net/can/j1939/bus.c +++ b/net/can/j1939/bus.c @@ -290,8 +290,11 @@ int j1939_local_ecu_get(struct j1939_priv *priv, name_t name, u8 sa) if (!ecu) ecu = j1939_ecu_create_locked(priv, name); err = PTR_ERR_OR_ZERO(ecu); - if (err) + if (err) { + if (j1939_address_is_unicast(sa)) + priv->ents[sa].nusers--; goto done; + } ecu->nusers++; /* TODO: do we care if ecu->addr != sa? */ From ef79f00be72bd81d2e1e6f060d83cf7e425deee4 Mon Sep 17 00:00:00 2001 From: Anssi Hannula Date: Fri, 22 Aug 2025 12:50:02 +0300 Subject: [PATCH 6/7] can: xilinx_can: xcan_write_frame(): fix use-after-free of transmitted SKB can_put_echo_skb() takes ownership of the SKB and it may be freed during or after the call. However, xilinx_can xcan_write_frame() keeps using SKB after the call. Fix that by only calling can_put_echo_skb() after the code is done touching the SKB. The tx_lock is held for the entire xcan_write_frame() execution and also on the can_get_echo_skb() side so the order of operations does not matter. An earlier fix commit 3d3c817c3a40 ("can: xilinx_can: Fix usage of skb memory") did not move the can_put_echo_skb() call far enough. Signed-off-by: Anssi Hannula Fixes: 1598efe57b3e ("can: xilinx_can: refactor code in preparation for CAN FD support") Link: https://patch.msgid.link/20250822095002.168389-1-anssi.hannula@bitwise.fi [mkl: add "commit" in front of sha1 in patch description] [mkl: fix indention] Signed-off-by: Marc Kleine-Budde --- drivers/net/can/xilinx_can.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index 81baec8eb1e5..a25a3ca62c12 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -690,14 +690,6 @@ static void xcan_write_frame(struct net_device *ndev, struct sk_buff *skb, dlc |= XCAN_DLCR_EDL_MASK; } - if (!(priv->devtype.flags & XCAN_FLAG_TX_MAILBOXES) && - (priv->devtype.flags & XCAN_FLAG_TXFEMP)) - can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max, 0); - else - can_put_echo_skb(skb, ndev, 0, 0); - - priv->tx_head++; - priv->write_reg(priv, XCAN_FRAME_ID_OFFSET(frame_offset), id); /* If the CAN frame is RTR frame this write triggers transmission * (not on CAN FD) @@ -730,6 +722,14 @@ static void xcan_write_frame(struct net_device *ndev, struct sk_buff *skb, data[1]); } } + + if (!(priv->devtype.flags & XCAN_FLAG_TX_MAILBOXES) && + (priv->devtype.flags & XCAN_FLAG_TXFEMP)) + can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max, 0); + else + can_put_echo_skb(skb, ndev, 0, 0); + + priv->tx_head++; } /** From 5c793afa07da6d2d4595f6c73a2a543a471bb055 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Thu, 14 Aug 2025 13:26:37 +0200 Subject: [PATCH 7/7] can: rcar_can: rcar_can_resume(): fix s2ram with PSCI On R-Car Gen3 using PSCI, s2ram powers down the SoC. After resume, the CAN interface no longer works, until it is brought down and up again. Fix this by calling rcar_can_start() from the PM resume callback, to fully initialize the controller instead of just restarting it. Signed-off-by: Geert Uytterhoeven Link: https://patch.msgid.link/699b2f7fcb60b31b6f976a37f08ce99c5ffccb31.1755165227.git.geert+renesas@glider.be Signed-off-by: Marc Kleine-Budde --- drivers/net/can/rcar/rcar_can.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/drivers/net/can/rcar/rcar_can.c b/drivers/net/can/rcar/rcar_can.c index 64e664f5adcc..87c134bcd48d 100644 --- a/drivers/net/can/rcar/rcar_can.c +++ b/drivers/net/can/rcar/rcar_can.c @@ -861,7 +861,6 @@ static int rcar_can_resume(struct device *dev) { struct net_device *ndev = dev_get_drvdata(dev); struct rcar_can_priv *priv = netdev_priv(ndev); - u16 ctlr; int err; if (!netif_running(ndev)) @@ -873,12 +872,7 @@ static int rcar_can_resume(struct device *dev) return err; } - ctlr = readw(&priv->regs->ctlr); - ctlr &= ~RCAR_CAN_CTLR_SLPM; - writew(ctlr, &priv->regs->ctlr); - ctlr &= ~RCAR_CAN_CTLR_CANM; - writew(ctlr, &priv->regs->ctlr); - priv->can.state = CAN_STATE_ERROR_ACTIVE; + rcar_can_start(ndev); netif_device_attach(ndev); netif_start_queue(ndev);