kernel/linux.git/net/can/j1939/socket.c, branch linux-7.1.y

net: change sock_queue_rcv_skb_reason() to return a drop_reason

2026-04-12T21:30:25+00:00

Change sock_queue_rcv_skb_reason() to return the drop_reason directly instead of using a reference. This is part of an effort to remove stack canaries and reduce bloat. $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/0 grow/shrink: 3/7 up/down: 79/-301 (-222) Function old new delta vsock_queue_rcv_skb 50 79 +29 ipmr_cache_report 1290 1315 +25 ip6mr_cache_report 1322 1347 +25 packet_rcv_spkt 329 327 -2 sock_queue_rcv_skb_reason 166 128 -38 raw_rcv_skb 122 80 -42 ping_queue_rcv_skb 109 61 -48 ping_rcv 215 162 -53 rawv6_rcv_skb 278 224 -54 raw_rcv 591 527 -64 Total: Before=29722890, After=29722668, chg -0.00% Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260409145625.2306224-2-edumazet@google.com Signed-off-by: Jakub Kicinski

can: remove private CAN skb headroom infrastructure

2026-02-05T10:58:40+00:00

This patch removes struct can_skb_priv which was stored at skb->head and the can_skb_reserve() helper which was used to shift skb->head. Signed-off-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260201-can_skb_ext-v8-5-3635d790fe8b@hartkopp.net Signed-off-by: Paolo Abeni

can: move ifindex to CAN skb extensions

2026-02-05T10:58:40+00:00

When routing CAN frames over different CAN interfaces the interface index skb->iif is overwritten with every single hop. To prevent sending a CAN frame back to its originating (first) incoming CAN interface another ifindex variable is needed, which was stored in can_skb_priv::ifindex. Move the can_skb_priv::ifindex content to can_skb_ext::can_iif. Signed-off-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260201-can_skb_ext-v8-3-3635d790fe8b@hartkopp.net Signed-off-by: Paolo Abeni

can: add CAN skb extension infrastructure

2026-02-05T10:58:39+00:00

To remove the private CAN bus skb headroom infrastructure 8 bytes need to be stored in the skb. The skb extensions are a common pattern and an easy and efficient way to hold private data travelling along with the skb. We only need the skb_ext_add() and skb_ext_find() functions to allocate and access CAN specific content as the skb helpers to copy/clone/free skbs automatically take care of skb extensions and their final removal. This patch introduces the complete CAN skb extensions infrastructure: - add struct can_skb_ext in new file include/net/can.h - add include/net/can.h in MAINTAINERS - add SKB_EXT_CAN to skbuff.c and skbuff.h - select SKB_EXTENSIONS in Kconfig when CONFIG_CAN is enabled - check for existing CAN skb extensions in can_rcv() in af_can.c - add CAN skb extensions allocation at every skb_alloc() location - duplicate the skb extensions if cloning outgoing skbs (framelen/gw_hops) - introduce can_skb_ext_add() and can_skb_ext_find() helpers The patch also corrects an indention issue in the original code from 2018: Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202602010426.PnGrYAk3-lkp@intel.com/ Signed-off-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260201-can_skb_ext-v8-2-3635d790fe8b@hartkopp.net Signed-off-by: Paolo Abeni

can: use skb hash instead of private variable in headroom

2026-02-05T10:58:39+00:00

The can_skb_priv::skbcnt variable is used to identify CAN skbs in the RX path analogue to the skb->hash. As the skb hash is not filled in CAN skbs move the private skbcnt value to skb->hash and set skb->sw_hash accordingly. The skb->hash is a value used for RPS to identify skbs. Use it as intended. Signed-off-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260201-can_skb_ext-v8-1-3635d790fe8b@hartkopp.net Signed-off-by: Paolo Abeni

can: j1939: make j1939_sk_bind() fail if device is no longer registered

2025-12-17T09:47:33+00:00

There is a theoretical race window in j1939_sk_netdev_event_unregister() where two j1939_sk_bind() calls jump in between read_unlock_bh() and lock_sock(). The assumption jsk->priv == priv can fail if the first j1939_sk_bind() call once made jsk->priv == NULL due to failed j1939_local_ecu_get() call and the second j1939_sk_bind() call again made jsk->priv != NULL due to successful j1939_local_ecu_get() call. Since the socket lock is held by both j1939_sk_netdev_event_unregister() and j1939_sk_bind(), checking ndev->reg_state with the socket lock held can reliably make the second j1939_sk_bind() call fail (and close this race window). Fixes: 7fcbe5b2c6a4 ("can: j1939: implement NETDEV_UNREGISTER notification handler") Signed-off-by: Tetsuo Handa Acked-by: Oleksij Rempel Link: https://patch.msgid.link/5732921e-247e-4957-a364-da74bd7031d7@I-love.SAKURA.ne.jp Signed-off-by: Marc Kleine-Budde

net: Convert proto_ops connect() callbacks to use sockaddr_unsized

2025-11-05T03:10:32+00:00

Update all struct proto_ops connect() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook Link: https://patch.msgid.link/20251104002617.2752303-3-kees@kernel.org Signed-off-by: Jakub Kicinski

net: Convert proto_ops bind() callbacks to use sockaddr_unsized

2025-11-05T03:10:32+00:00

Update all struct proto_ops bind() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org Signed-off-by: Jakub Kicinski

can: j1939: j1939_sk_bind(): call j1939_priv_put() immediately when j1939_local_ecu_get() failed

2025-09-10T15:12:04+00:00

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

can: j1939: implement NETDEV_UNREGISTER notification handler

2025-09-10T15:12:04+00:00

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