vcan0: j1939_tp_txtimer: 0xffff888049289c00: tx aborted with unknown reason: -2
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc2-next-20230105-syzkaller #0 Not tainted
------------------------------------------------------
syz-fuzzer/5072 is trying to acquire lock:
ffff88807c63d0d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff88807c63d0d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_errqueue+0xa3/0x1a0 net/can/j1939/socket.c:1081

but task is already holding lock:
ffff88807c63d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff88807c63d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
ffff88807c63d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_cancel+0x40/0x1eb net/can/j1939/transport.c:1138

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:355 [inline]
       j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
       j1939_session_activate+0x47/0x4b0 net/can/j1939/transport.c:1561
       j1939_sk_queue_activate_next_locked net/can/j1939/socket.c:181 [inline]
       j1939_sk_queue_activate_next+0x1b6/0x450 net/can/j1939/socket.c:208
       j1939_session_deactivate_activate_next net/can/j1939/transport.c:1109 [inline]
       j1939_session_completed+0x19a/0x1f0 net/can/j1939/transport.c:1222
       j1939_xtp_rx_eoma_one net/can/j1939/transport.c:1392 [inline]
       j1939_xtp_rx_eoma+0x2a1/0x5e0 net/can/j1939/transport.c:1407
       j1939_tp_cmd_recv net/can/j1939/transport.c:2096 [inline]
       j1939_tp_recv+0x71c/0xcd0 net/can/j1939/transport.c:2141
       j1939_can_recv net/can/j1939/main.c:112 [inline]
       j1939_can_recv+0x78e/0xa30 net/can/j1939/main.c:38
       deliver net/can/af_can.c:572 [inline]
       can_rcv_filter+0x5d4/0x8d0 net/can/af_can.c:606
       can_receive+0x31d/0x5c0 net/can/af_can.c:663
       can_rcv+0x1e1/0x230 net/can/af_can.c:687
       __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5482
       __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5596
       process_backlog+0x13e/0x6d0 net/core/dev.c:5924
       __napi_poll+0xaf/0x430 net/core/dev.c:6485
       napi_poll net/core/dev.c:6552 [inline]
       net_rx_action+0x8da/0xc70 net/core/dev.c:6663
       __do_softirq+0x1fb/0xaf6 kernel/softirq.c:571
       run_ksoftirqd kernel/softirq.c:934 [inline]
       run_ksoftirqd+0x31/0x60 kernel/softirq.c:926
       smpboot_thread_fn+0x659/0xa30 kernel/smpboot.c:164
       kthread+0x2e8/0x3a0 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

-> #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:355 [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:1275
       j1939_netdev_notify+0x19d/0x1d0 net/can/j1939/main.c:379
       notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
       call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1944
       call_netdevice_notifiers_extack net/core/dev.c:1982 [inline]
       call_netdevice_notifiers net/core/dev.c:1996 [inline]
       __dev_notify_flags+0x1ea/0x2d0 net/core/dev.c:8571
       dev_change_flags+0x11b/0x170 net/core/dev.c:8607
       do_setlink+0x9f1/0x3bb0 net/core/rtnetlink.c:2827
       __rtnl_newlink+0xd69/0x1840 net/core/rtnetlink.c:3590
       rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3637
       rtnetlink_rcv_msg+0x43d/0xd50 net/core/rtnetlink.c:6141
       netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564
       netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
       netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
       netlink_sendmsg+0x925/0xe20 net/netlink/af_netlink.c:1932
       sock_sendmsg_nosec net/socket.c:714 [inline]
       sock_sendmsg+0xd3/0x120 net/socket.c:734
       ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
       ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
       __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&priv->j1939_socks_lock){+.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain kernel/locking/lockdep.c:3831 [inline]
       __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
       lock_acquire.part.0+0x11a/0x350 kernel/locking/lockdep.c:5668
       __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:355 [inline]
       j1939_sk_errqueue+0xa3/0x1a0 net/can/j1939/socket.c:1081
       __j1939_session_cancel+0x3b9/0x460 net/can/j1939/transport.c:1132
       j1939_session_cancel+0x1b1/0x1eb net/can/j1939/transport.c:1143
       j1939_tp_txtimer.cold+0x266/0x3ab net/can/j1939/transport.c:1198
       __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
       __hrtimer_run_queues+0x600/0xcf0 kernel/time/hrtimer.c:1749
       hrtimer_run_softirq+0x17f/0x360 kernel/time/hrtimer.c:1766
       __do_softirq+0x1fb/0xaf6 kernel/softirq.c:571
       do_softirq.part.0+0xde/0x130 kernel/softirq.c:472
       do_softirq kernel/softirq.c:464 [inline]
       __local_bh_enable_ip+0x106/0x130 kernel/softirq.c:396
       local_bh_enable include/linux/bottom_half.h:33 [inline]
       rcu_read_unlock_bh include/linux/rcupdate.h:843 [inline]
       ip_finish_output2+0x7dc/0x22e0 net/ipv4/ip_output.c:229
       __ip_finish_output net/ipv4/ip_output.c:306 [inline]
       __ip_finish_output+0x396/0x650 net/ipv4/ip_output.c:288
       ip_finish_output+0x31/0x280 net/ipv4/ip_output.c:316
       NF_HOOK_COND include/linux/netfilter.h:291 [inline]
       ip_output+0x1a3/0x320 net/ipv4/ip_output.c:430
       dst_output include/net/dst.h:444 [inline]
       ip_local_out net/ipv4/ip_output.c:126 [inline]
       __ip_queue_xmit+0x8e2/0x1c60 net/ipv4/ip_output.c:532
       __tcp_transmit_skb+0x1967/0x3820 net/ipv4/tcp_output.c:1399
       tcp_transmit_skb net/ipv4/tcp_output.c:1417 [inline]
       tcp_write_xmit+0x1025/0x6160 net/ipv4/tcp_output.c:2693
       __tcp_push_pending_frames+0xae/0x390 net/ipv4/tcp_output.c:2877
       tcp_push_pending_frames include/net/tcp.h:1946 [inline]
       tcp_data_snd_check net/ipv4/tcp_input.c:5510 [inline]
       tcp_rcv_established+0x931/0x2270 net/ipv4/tcp_input.c:6019
       tcp_v4_do_rcv+0x663/0x9d0 net/ipv4/tcp_ipv4.c:1721
       sk_backlog_rcv include/net/sock.h:1113 [inline]
       __release_sock+0x133/0x3b0 net/core/sock.c:2928
       release_sock+0x58/0x1b0 net/core/sock.c:3485
       tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1484
       inet_sendmsg+0x9d/0xe0 net/ipv4/af_inet.c:827
       sock_sendmsg_nosec net/socket.c:714 [inline]
       sock_sendmsg+0xd3/0x120 net/socket.c:734
       sock_write_iter+0x295/0x3d0 net/socket.c:1108
       call_write_iter include/linux/fs.h:2189 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x9ed/0xe10 fs/read_write.c:584
       ksys_write+0x1ec/0x250 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  &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 ***

3 locks held by syz-fuzzer/5072:
 #0: ffff888076df8130 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1725 [inline]
 #0: ffff888076df8130 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_sendmsg+0x21/0x50 net/ipv4/tcp.c:1482
 #1: ffffffff8c792d80 (rcu_read_lock){....}-{1:2}, at: read_pnet include/net/net_namespace.h:383 [inline]
 #1: ffffffff8c792d80 (rcu_read_lock){....}-{1:2}, at: sock_net include/net/sock.h:649 [inline]
 #1: ffffffff8c792d80 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x41/0x1c60 net/ipv4/ip_output.c:457
 #2: ffff88807c63d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
 #2: ffff88807c63d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
 #2: ffff88807c63d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_cancel+0x40/0x1eb net/can/j1939/transport.c:1138

stack backtrace:
CPU: 1 PID: 5072 Comm: syz-fuzzer Not tainted 6.2.0-rc2-next-20230105-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain kernel/locking/lockdep.c:3831 [inline]
 __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
 lock_acquire.part.0+0x11a/0x350 kernel/locking/lockdep.c:5668
 __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:355 [inline]
 j1939_sk_errqueue+0xa3/0x1a0 net/can/j1939/socket.c:1081
 __j1939_session_cancel+0x3b9/0x460 net/can/j1939/transport.c:1132
 j1939_session_cancel+0x1b1/0x1eb net/can/j1939/transport.c:1143
 j1939_tp_txtimer.cold+0x266/0x3ab net/can/j1939/transport.c:1198
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x600/0xcf0 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x17f/0x360 kernel/time/hrtimer.c:1766
 __do_softirq+0x1fb/0xaf6 kernel/softirq.c:571
 do_softirq.part.0+0xde/0x130 kernel/softirq.c:472
 </IRQ>
 <TASK>
 do_softirq kernel/softirq.c:464 [inline]
 __local_bh_enable_ip+0x106/0x130 kernel/softirq.c:396
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:843 [inline]
 ip_finish_output2+0x7dc/0x22e0 net/ipv4/ip_output.c:229
 __ip_finish_output net/ipv4/ip_output.c:306 [inline]
 __ip_finish_output+0x396/0x650 net/ipv4/ip_output.c:288
 ip_finish_output+0x31/0x280 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip_output+0x1a3/0x320 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:444 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0x8e2/0x1c60 net/ipv4/ip_output.c:532
 __tcp_transmit_skb+0x1967/0x3820 net/ipv4/tcp_output.c:1399
 tcp_transmit_skb net/ipv4/tcp_output.c:1417 [inline]
 tcp_write_xmit+0x1025/0x6160 net/ipv4/tcp_output.c:2693
 __tcp_push_pending_frames+0xae/0x390 net/ipv4/tcp_output.c:2877
 tcp_push_pending_frames include/net/tcp.h:1946 [inline]
 tcp_data_snd_check net/ipv4/tcp_input.c:5510 [inline]
 tcp_rcv_established+0x931/0x2270 net/ipv4/tcp_input.c:6019
 tcp_v4_do_rcv+0x663/0x9d0 net/ipv4/tcp_ipv4.c:1721
 sk_backlog_rcv include/net/sock.h:1113 [inline]
 __release_sock+0x133/0x3b0 net/core/sock.c:2928
 release_sock+0x58/0x1b0 net/core/sock.c:3485
 tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1484
 inet_sendmsg+0x9d/0xe0 net/ipv4/af_inet.c:827
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xd3/0x120 net/socket.c:734
 sock_write_iter+0x295/0x3d0 net/socket.c:1108
 call_write_iter include/linux/fs.h:2189 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x9ed/0xe10 fs/read_write.c:584
 ksys_write+0x1ec/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x4adffb
Code: e8 8a 58 fb ff eb 88 cc cc cc cc cc cc cc cc e8 9b 9c fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 28 ff ff ff ff 48 c7 44 24 30
RSP: 002b:000000c002567378 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000c000040800 RCX: 00000000004adffb
RDX: 00000000000000f0 RSI: 000000c00000a200 RDI: 0000000000000003
RBP: 000000c0025673c8 R08: 0000000000000001 R09: 000000c0006c0200
R10: 00000000000000f0 R11: 0000000000000212 R12: 000000c002567458
R13: 0000000000000000 R14: 000000c0004104e0 R15: 000000000000007f
 </TASK>
vcan0: j1939_tp_rxtimer: 0xffff888049289c00: abort rx timeout. Force session deactivation
TCP: request_sock_TCPv6: Possible SYN flooding on port [::1]:20002. Sending cookies.
TCP: request_sock_TCPv6: Possible SYN flooding on port [::1]:20002. Sending cookies.