syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.32-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/18460 is trying to acquire lock:
ffff8880731225c8 (&jsk->sk_session_queue_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff8880731225c8 (&jsk->sk_session_queue_lock){+.-.}-{2:2}, at: j1939_sk_queue_drop_all+0x3a/0x240 net/can/j1939/socket.c:139

but task is already holding lock:
ffff888029a110d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff888029a110d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_netdev_event_netdown+0x2d/0x150 net/can/j1939/socket.c:1269

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&priv->j1939_socks_lock){+.-.}-{2:2}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:355 [inline]
       j1939_sk_errqueue+0x92/0x140 net/can/j1939/socket.c:1081
       __j1939_session_release net/can/j1939/transport.c:294 [inline]
       kref_put include/linux/kref.h:65 [inline]
       j1939_session_put+0x100/0x460 net/can/j1939/transport.c:299
       j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline]
       j1939_cancel_active_session+0x350/0x480 net/can/j1939/transport.c:2194
       j1939_netdev_notify+0x1ff/0x2e0 net/can/j1939/main.c:378
       notifier_call_chain kernel/notifier.c:87 [inline]
       raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:455
       call_netdevice_notifiers_info net/core/dev.c:1945 [inline]
       call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]
       call_netdevice_notifiers net/core/dev.c:1997 [inline]
       dev_close_many+0x37c/0x530 net/core/dev.c:1545
       unregister_netdevice_many+0x4d0/0x1870 net/core/dev.c:10818
       rtnl_delete_link net/core/rtnetlink.c:3123 [inline]
       rtnl_dellink+0x4e1/0x880 net/core/rtnetlink.c:3174
       rtnetlink_rcv_msg+0x776/0xf00 net/core/rtnetlink.c:6091
       netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2524
       netlink_unicast_kernel net/netlink/af_netlink.c:1328 [inline]
       netlink_unicast+0x7bf/0x990 net/netlink/af_netlink.c:1354
       netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1902
       sock_sendmsg_nosec net/socket.c:716 [inline]
       sock_sendmsg net/socket.c:736 [inline]
       ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2482
       ___sys_sendmsg net/socket.c:2536 [inline]
       __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&priv->active_session_list_lock){+.-.}-{2:2}
:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x31/0x40 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+0x4d/0x3d0 net/can/j1939/transport.c:1564
       j1939_sk_queue_activate_next_locked net/can/j1939/socket.c:181 [inline]
       j1939_sk_queue_activate_next+0x268/0x3e0 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+0x323/0x530 net/can/j1939/transport.c:1410
       j1939_tp_cmd_recv net/can/j1939/transport.c:2099 [inline]
       j1939_tp_recv+0x833/0x1000 net/can/j1939/transport.c:2144
       j1939_can_recv+0x72e/0xb10 net/can/j1939/main.c:112
       deliver net/can/af_can.c:573 [inline]
       can_rcv_filter+0x349/0x7c0 net/can/af_can.c:607
       can_receive+0x2f2/0x430 net/can/af_can.c:664
       can_rcv+0x140/0x260 net/can/af_can.c:688
       __netif_receive_skb_one_core net/core/dev.c:5494 [inline]
       __netif_receive_skb+0x1c6/0x530 net/core/dev.c:5608
       process_backlog+0x347/0x700 net/core/dev.c:5936
       __napi_poll+0xc7/0x470 net/core/dev.c:6503
       napi_poll net/core/dev.c:6570 [inline]
       net_rx_action+0x70f/0xeb0 net/core/dev.c:6681
       __do_softirq+0x2e9/0xa4c kernel/softirq.c:571
       invoke_softirq kernel/softirq.c:445 [inline]
       __irq_exit_rcu+0x155/0x240 kernel/softirq.c:650
       irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
       sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106
       asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
       finish_lock_switch+0x91/0x100 kernel/sched/core.c:5001
       finish_task_switch+0x134/0x630 kernel/sched/core.c:5118
       context_switch kernel/sched/core.c:5244 [inline]
       __schedule+0x1334/0x4330 kernel/sched/core.c:6554
       schedule+0xbf/0x180 kernel/sched/core.c:6630
       schedule_timeout+0xac/0x300 kernel/time/timer.c:1911
       unix_wait_for_peer+0x24b/0x330 net/unix/af_unix.c:1449
       unix_dgram_sendmsg+0x1348/0x2050 net/unix/af_unix.c:2047
       sock_sendmsg_nosec net/socket.c:716 [inline]
       sock_sendmsg net/socket.c:736 [inline]
       ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2482
       ___sys_sendmsg net/socket.c:2536 [inline]
       __sys_sendmmsg+0x3ab/0x730 net/socket.c:2622
       __do_sys_sendmmsg net/socket.c:2651 [inline]
       __se_sys_sendmmsg net/socket.c:2648 [inline]
       __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2648
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&jsk->sk_session_queue_lock){+.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3098 [inline]
       check_prevs_add kernel/locking/lockdep.c:3217 [inline]
       validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:355 [inline]
       j1939_sk_queue_drop_all+0x3a/0x240 net/can/j1939/socket.c:139
       j1939_sk_netdev_event_netdown+0xe9/0x150 net/can/j1939/socket.c:1275
       j1939_netdev_notify+0x207/0x2e0 net/can/j1939/main.c:379
       notifier_call_chain kernel/notifier.c:87 [inline]
       raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:455
       call_netdevice_notifiers_info net/core/dev.c:1945 [inline]
       call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]
       call_netdevice_notifiers net/core/dev.c:1997 [inline]
       dev_close_many+0x37c/0x530 net/core/dev.c:1545
       unregister_netdevice_many+0x4d0/0x1870 net/core/dev.c:10818
       rtnl_delete_link net/core/rtnetlink.c:3123 [inline]
       rtnl_dellink+0x4e1/0x880 net/core/rtnetlink.c:3174
       rtnetlink_rcv_msg+0x776/0xf00 net/core/rtnetlink.c:6091
       netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2524
       netlink_unicast_kernel net/netlink/af_netlink.c:1328 [inline]
       netlink_unicast+0x7bf/0x990 net/netlink/af_netlink.c:1354
       netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1902
       sock_sendmsg_nosec net/socket.c:716 [inline]
       sock_sendmsg net/socket.c:736 [inline]
       ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2482
       ___sys_sendmsg net/socket.c:2536 [inline]
       __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

2 locks held by syz-executor.1/18460:
 #0: ffffffff8e093c08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8e093c08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x720/0xf00 net/core/rtnetlink.c:6088
 #1: ffff888029a110d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
 #1: ffff888029a110d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_netdev_event_netdown+0x2d/0x150 net/can/j1939/socket.c:1269

stack backtrace:
CPU: 1 PID: 18460 Comm: syz-executor.1 Not tainted 6.1.32-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3098 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:355 [inline]
 j1939_sk_queue_drop_all+0x3a/0x240 net/can/j1939/socket.c:139
 j1939_sk_netdev_event_netdown+0xe9/0x150 net/can/j1939/socket.c:1275
 j1939_netdev_notify+0x207/0x2e0 net/can/j1939/main.c:379
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:455
 call_netdevice_notifiers_info net/core/dev.c:1945 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]
 call_netdevice_notifiers net/core/dev.c:1997 [inline]
 dev_close_many+0x37c/0x530 net/core/dev.c:1545
 unregister_netdevice_many+0x4d0/0x1870 net/core/dev.c:10818
 rtnl_delete_link net/core/rtnetlink.c:3123 [inline]
 rtnl_dellink+0x4e1/0x880 net/core/rtnetlink.c:3174
 rtnetlink_rcv_msg+0x776/0xf00 net/core/rtnetlink.c:6091
 netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2524
 netlink_unicast_kernel net/netlink/af_netlink.c:1328 [inline]
 netlink_unicast+0x7bf/0x990 net/netlink/af_netlink.c:1354
 netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1902
 sock_sendmsg_nosec net/socket.c:716 [inline]
 sock_sendmsg net/socket.c:736 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f531068c169
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f531148c168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f53107ac050 RCX: 00007f531068c169
RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 000000000000000c
RBP: 00007f53106e7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff5958f37f R14: 00007f531148c300 R15: 0000000000022000
 </TASK>