netlink: 'syz-executor.2': attribute type 27 has an invalid length.
======================================================
WARNING: possible circular locking dependency detected
6.7.0-syzkaller-11091-g296455ade1fd #0 Not tainted
------------------------------------------------------
syz-executor.2/16752 is trying to acquire lock:
ffff88802c6a90d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff88802c6a90d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_errqueue+0xaa/0x1a0 net/can/j1939/socket.c:1083

but task is already holding lock:
ffff88802c6a9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff88802c6a9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
ffff88802c6a9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x41/0x360 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+0x33/0x40 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:356 [inline]
       j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
       j1939_session_activate+0x4b/0x4a0 net/can/j1939/transport.c:1564
       j1939_sk_queue_activate_next_locked net/can/j1939/socket.c:181 [inline]
       j1939_sk_queue_activate_next+0x2bc/0x4d0 net/can/j1939/socket.c:208
       j1939_session_deactivate_activate_next net/can/j1939/transport.c:1108 [inline]
       j1939_session_completed+0xb7/0x170 net/can/j1939/transport.c:1222
       j1939_xtp_rx_eoma_one net/can/j1939/transport.c:1395 [inline]
       j1939_xtp_rx_eoma+0x293/0x600 net/can/j1939/transport.c:1410
       j1939_tp_cmd_recv net/can/j1939/transport.c:2099 [inline]
       j1939_tp_recv+0x718/0xf50 net/can/j1939/transport.c:2144
       j1939_can_recv+0x78b/0xa70 net/can/j1939/main.c:112
       deliver net/can/af_can.c:572 [inline]
       can_rcv_filter+0x2a5/0x8e0 net/can/af_can.c:606
       can_receive+0x320/0x5c0 net/can/af_can.c:663
       can_rcv+0x1dc/0x270 net/can/af_can.c:687
       __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5534
       __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5648
       process_backlog+0x101/0x6b0 net/core/dev.c:5976
       __napi_poll.constprop.0+0xb4/0x540 net/core/dev.c:6576
       napi_poll net/core/dev.c:6645 [inline]
       net_rx_action+0x956/0xe90 net/core/dev.c:6778
       __do_softirq+0x21a/0x8de kernel/softirq.c:553
       do_softirq kernel/softirq.c:454 [inline]
       do_softirq+0xaa/0xe0 kernel/softirq.c:441
       __local_bh_enable_ip+0xfc/0x120 kernel/softirq.c:381
       spin_unlock_bh include/linux/spinlock.h:396 [inline]
       nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline]
       nsim_dev_trap_report_work+0x870/0xc80 drivers/net/netdevsim/dev.c:850
       process_one_work+0x886/0x15d0 kernel/workqueue.c:2633
       process_scheduled_works kernel/workqueue.c:2706 [inline]
       worker_thread+0x8b9/0x1290 kernel/workqueue.c:2787
       kthread+0x2c6/0x3a0 kernel/kthread.c:388
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

-> #1 (&jsk->sk_session_queue_lock){+.-.}-{2:2}:
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:356 [inline]
       j1939_sk_queue_drop_all+0x3b/0x2f0 net/can/j1939/socket.c:139
       j1939_sk_netdev_event_netdown+0x7f/0x160 net/can/j1939/socket.c:1282
       j1939_netdev_notify+0x1a2/0x1d0 net/can/j1939/main.c:381
       notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
       call_netdevice_notifiers_info+0xbe/0x130 net/core/dev.c:1966
       call_netdevice_notifiers_extack net/core/dev.c:2004 [inline]
       call_netdevice_notifiers net/core/dev.c:2018 [inline]
       __dev_notify_flags+0x1f5/0x2e0 net/core/dev.c:8689
       dev_change_flags+0x10c/0x160 net/core/dev.c:8725
       do_setlink+0x1a73/0x4090 net/core/rtnetlink.c:2910
       rtnl_group_changelink net/core/rtnetlink.c:3452 [inline]
       __rtnl_newlink+0xe04/0x1940 net/core/rtnetlink.c:3711
       rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3748
       rtnetlink_rcv_msg+0x3c7/0xe00 net/core/rtnetlink.c:6615
       netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2543
       netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
       netlink_unicast+0x53b/0x810 net/netlink/af_netlink.c:1367
       netlink_sendmsg+0x8b7/0xd70 net/netlink/af_netlink.c:1908
       sock_sendmsg_nosec net/socket.c:730 [inline]
       __sock_sendmsg+0xd5/0x180 net/socket.c:745
       ____sys_sendmsg+0x6ac/0x940 net/socket.c:2584
       ___sys_sendmsg+0x135/0x1d0 net/socket.c:2638
       __sys_sendmsg+0x117/0x1e0 net/socket.c:2667
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

-> #0 (&priv->j1939_socks_lock){+.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2445/0x3b30 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:356 [inline]
       j1939_sk_errqueue+0xaa/0x1a0 net/can/j1939/socket.c:1083
       j1939_session_destroy+0x276/0x4f0 net/can/j1939/transport.c:271
       __j1939_session_release net/can/j1939/transport.c:294 [inline]
       kref_put include/linux/kref.h:65 [inline]
       j1939_session_put net/can/j1939/transport.c:299 [inline]
       j1939_session_deactivate_locked+0x28e/0x330 net/can/j1939/transport.c:1086
       j1939_cancel_active_session+0x183/0x360 net/can/j1939/transport.c:2194
       j1939_netdev_notify+0x19a/0x1d0 net/can/j1939/main.c:380
       notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
       call_netdevice_notifiers_info+0xbe/0x130 net/core/dev.c:1966
       call_netdevice_notifiers_extack net/core/dev.c:2004 [inline]
       call_netdevice_notifiers net/core/dev.c:2018 [inline]
       __dev_notify_flags+0x1f5/0x2e0 net/core/dev.c:8689
       dev_change_flags+0x10c/0x160 net/core/dev.c:8725
       do_setlink+0x1a73/0x4090 net/core/rtnetlink.c:2910
       rtnl_group_changelink net/core/rtnetlink.c:3452 [inline]
       __rtnl_newlink+0xe04/0x1940 net/core/rtnetlink.c:3711
       rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3748
       rtnetlink_rcv_msg+0x3c7/0xe00 net/core/rtnetlink.c:6615
       netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2543
       netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
       netlink_unicast+0x53b/0x810 net/netlink/af_netlink.c:1367
       netlink_sendmsg+0x8b7/0xd70 net/netlink/af_netlink.c:1908
       sock_sendmsg_nosec net/socket.c:730 [inline]
       __sock_sendmsg+0xd5/0x180 net/socket.c:745
       ____sys_sendmsg+0x6ac/0x940 net/socket.c:2584
       ___sys_sendmsg+0x135/0x1d0 net/socket.c:2638
       __sys_sendmsg+0x117/0x1e0 net/socket.c:2667
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

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.2/16752:
 #0: ffffffff8ecb2568 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8ecb2568 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xe00 net/core/rtnetlink.c:6612
 #1: ffff88802c6a9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
 #1: ffff88802c6a9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
 #1: ffff88802c6a9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x41/0x360 net/can/j1939/transport.c:2183

stack backtrace:
CPU: 2 PID: 16752 Comm: syz-executor.2 Not tainted 6.7.0-syzkaller-11091-g296455ade1fd #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_noncircular+0x317/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2445/0x3b30 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 j1939_sk_errqueue+0xaa/0x1a0 net/can/j1939/socket.c:1083
 j1939_session_destroy+0x276/0x4f0 net/can/j1939/transport.c:271
 __j1939_session_release net/can/j1939/transport.c:294 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put net/can/j1939/transport.c:299 [inline]
 j1939_session_deactivate_locked+0x28e/0x330 net/can/j1939/transport.c:1086
 j1939_cancel_active_session+0x183/0x360 net/can/j1939/transport.c:2194
 j1939_netdev_notify+0x19a/0x1d0 net/can/j1939/main.c:380
 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xbe/0x130 net/core/dev.c:1966
 call_netdevice_notifiers_extack net/core/dev.c:2004 [inline]
 call_netdevice_notifiers net/core/dev.c:2018 [inline]
 __dev_notify_flags+0x1f5/0x2e0 net/core/dev.c:8689
 dev_change_flags+0x10c/0x160 net/core/dev.c:8725
 do_setlink+0x1a73/0x4090 net/core/rtnetlink.c:2910
 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline]
 __rtnl_newlink+0xe04/0x1940 net/core/rtnetlink.c:3711
 rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3748
 rtnetlink_rcv_msg+0x3c7/0xe00 net/core/rtnetlink.c:6615
 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2543
 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
 netlink_unicast+0x53b/0x810 net/netlink/af_netlink.c:1367
 netlink_sendmsg+0x8b7/0xd70 net/netlink/af_netlink.c:1908
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0xd5/0x180 net/socket.c:745
 ____sys_sendmsg+0x6ac/0x940 net/socket.c:2584
 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2638
 __sys_sendmsg+0x117/0x1e0 net/socket.c:2667
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f7a2fe7cda9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7a30b460c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f7a2ffabf80 RCX: 00007f7a2fe7cda9
RDX: 0000000000000000 RSI: 0000000020006440 RDI: 0000000000000006
RBP: 00007f7a2fec947a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f7a2ffabf80 R15: 00007fff48ef2d68
 </TASK>