netlink: 'syz-executor.0': attribute type 27 has an invalid length.
======================================================
WARNING: possible circular locking dependency detected
6.1.73-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/22318 is trying to acquire lock:
ffff0000d59550d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff0000d59550d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1083

but task is already holding lock:
ffff0000d5955088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff0000d5955088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
ffff0000d5955088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x54/0x414 net/can/j1939/transport.c:2183

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&priv->active_session_list_lock){+.-.}-{2:2}:
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x54/0x6c kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:355 [inline]
       j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
       j1939_session_activate+0x60/0x378 net/can/j1939/transport.c:1564
       j1939_sk_queue_activate_next_locked net/can/j1939/socket.c:181 [inline]
       j1939_sk_queue_activate_next+0x230/0x3b4 net/can/j1939/socket.c:208
       j1939_session_deactivate_activate_next net/can/j1939/transport.c:1108 [inline]
       j1939_session_completed net/can/j1939/transport.c:1222 [inline]
       j1939_xtp_rx_eoma_one net/can/j1939/transport.c:1395 [inline]
       j1939_xtp_rx_eoma+0x2c0/0x4c0 net/can/j1939/transport.c:1410
       j1939_tp_cmd_recv net/can/j1939/transport.c:2099 [inline]
       j1939_tp_recv+0x714/0xe14 net/can/j1939/transport.c:2144
       j1939_can_recv+0x5d0/0x948 net/can/j1939/main.c:112
       deliver net/can/af_can.c:573 [inline]
       can_rcv_filter+0x308/0x714 net/can/af_can.c:607
       can_receive+0x338/0x498 net/can/af_can.c:664
       can_rcv+0x128/0x240 net/can/af_can.c:688
       __netif_receive_skb_one_core net/core/dev.c:5528 [inline]
       __netif_receive_skb+0x18c/0x400 net/core/dev.c:5642
       process_backlog+0x410/0x784 net/core/dev.c:5970
       __napi_poll+0xb4/0x3f0 net/core/dev.c:6537
       napi_poll net/core/dev.c:6604 [inline]
       net_rx_action+0x5cc/0xd3c net/core/dev.c:6715
       __do_softirq+0x314/0xe38 kernel/softirq.c:571
       run_ksoftirqd+0x68/0x258 kernel/softirq.c:934
       smpboot_thread_fn+0x4b0/0x96c kernel/smpboot.c:164
       kthread+0x250/0x2d8 kernel/kthread.c:376
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864

-> #1 (&jsk->sk_session_queue_lock){+.-.}-{2:2}:
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x54/0x6c kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:355 [inline]
       j1939_sk_queue_drop_all+0x4c/0x200 net/can/j1939/socket.c:139
       j1939_sk_netdev_event_netdown+0xe0/0x144 net/can/j1939/socket.c:1282
       j1939_netdev_notify+0xf0/0x144 net/can/j1939/main.c:381
       notifier_call_chain kernel/notifier.c:87 [inline]
       raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
       __dev_notify_flags+0x2ac/0x534
       dev_change_flags+0xc8/0x154 net/core/dev.c:8658
       do_setlink+0xc70/0x3328 net/core/rtnetlink.c:2808
       rtnl_group_changelink net/core/rtnetlink.c:3329 [inline]
       __rtnl_newlink net/core/rtnetlink.c:3586 [inline]
       rtnl_newlink+0xe2c/0x1b74 net/core/rtnetlink.c:3623
       rtnetlink_rcv_msg+0x72c/0xd94 net/core/rtnetlink.c:6122
       netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2508
       rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6140
       netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
       netlink_unicast+0x65c/0x898 net/netlink/af_netlink.c:1352
       netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1874
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:730 [inline]
       ____sys_sendmsg+0x55c/0x848 net/socket.c:2514
       ___sys_sendmsg net/socket.c:2568 [inline]
       __sys_sendmsg+0x26c/0x33c net/socket.c:2597
       __do_sys_sendmsg net/socket.c:2606 [inline]
       __se_sys_sendmsg net/socket.c:2604 [inline]
       __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2604
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (&priv->j1939_socks_lock){+.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
       lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x54/0x6c kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:355 [inline]
       j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1083
       __j1939_session_release net/can/j1939/transport.c:294 [inline]
       kref_put include/linux/kref.h:65 [inline]
       j1939_session_put+0xf0/0x4b4 net/can/j1939/transport.c:299
       j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline]
       j1939_cancel_active_session+0x2ec/0x414 net/can/j1939/transport.c:2194
       j1939_netdev_notify+0xe8/0x144 net/can/j1939/main.c:380
       notifier_call_chain kernel/notifier.c:87 [inline]
       raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
       __dev_notify_flags+0x2ac/0x534
       dev_change_flags+0xc8/0x154 net/core/dev.c:8658
       do_setlink+0xc70/0x3328 net/core/rtnetlink.c:2808
       rtnl_group_changelink net/core/rtnetlink.c:3329 [inline]
       __rtnl_newlink net/core/rtnetlink.c:3586 [inline]
       rtnl_newlink+0xe2c/0x1b74 net/core/rtnetlink.c:3623
       rtnetlink_rcv_msg+0x72c/0xd94 net/core/rtnetlink.c:6122
       netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2508
       rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6140
       netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
       netlink_unicast+0x65c/0x898 net/netlink/af_netlink.c:1352
       netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1874
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:730 [inline]
       ____sys_sendmsg+0x55c/0x848 net/socket.c:2514
       ___sys_sendmsg net/socket.c:2568 [inline]
       __sys_sendmsg+0x26c/0x33c net/socket.c:2597
       __do_sys_sendmsg net/socket.c:2606 [inline]
       __se_sys_sendmsg net/socket.c:2604 [inline]
       __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2604
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Chain exists of:
  &priv->j1939_socks_lock --> &jsk->sk_session_queue_lock --> &priv->active_session_list_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&priv->active_session_list_lock);
                               lock(&jsk->sk_session_queue_lock);
                               lock(&priv->active_session_list_lock);
  lock(&priv->j1939_socks_lock);

 *** DEADLOCK ***

2 locks held by syz-executor.0/22318:
 #0: ffff800017df9408 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff800017df9408 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e8/0xd94 net/core/rtnetlink.c:6119
 #1: ffff0000d5955088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
 #1: ffff0000d5955088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
 #1: ffff0000d5955088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x54/0x414 net/can/j1939/transport.c:2183

stack backtrace:
CPU: 1 PID: 22318 Comm: syz-executor.0 Not tainted 6.1.73-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2048
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x54/0x6c kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:355 [inline]
 j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1083
 __j1939_session_release net/can/j1939/transport.c:294 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put+0xf0/0x4b4 net/can/j1939/transport.c:299
 j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline]
 j1939_cancel_active_session+0x2ec/0x414 net/can/j1939/transport.c:2194
 j1939_netdev_notify+0xe8/0x144 net/can/j1939/main.c:380
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
 __dev_notify_flags+0x2ac/0x534
 dev_change_flags+0xc8/0x154 net/core/dev.c:8658
 do_setlink+0xc70/0x3328 net/core/rtnetlink.c:2808
 rtnl_group_changelink net/core/rtnetlink.c:3329 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3586 [inline]
 rtnl_newlink+0xe2c/0x1b74 net/core/rtnetlink.c:3623
 rtnetlink_rcv_msg+0x72c/0xd94 net/core/rtnetlink.c:6122
 netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2508
 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6140
 netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
 netlink_unicast+0x65c/0x898 net/netlink/af_netlink.c:1352
 netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1874
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x55c/0x848 net/socket.c:2514
 ___sys_sendmsg net/socket.c:2568 [inline]
 __sys_sendmsg+0x26c/0x33c net/socket.c:2597
 __do_sys_sendmsg net/socket.c:2606 [inline]
 __se_sys_sendmsg net/socket.c:2604 [inline]
 __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2604
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585