netlink: 'syz-executor.4': attribute type 27 has an invalid length. ====================================================== WARNING: possible circular locking dependency detected 6.8.0-rc2-syzkaller-00055-g6764c317b6bb #0 Not tainted ------------------------------------------------------ syz-executor.4/17065 is trying to acquire lock: ffff88801e6610d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff88801e6610d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_errqueue+0x96/0x150 net/can/j1939/socket.c:1083 but task is already holding lock: ffff88801e661088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff88801e661088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline] ffff88801e661088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x47/0x490 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}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 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+0x51/0x3e0 net/can/j1939/transport.c:1564 j1939_sk_queue_activate_next_locked net/can/j1939/socket.c:181 [inline] j1939_sk_queue_activate_next+0x270/0x3f0 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+0x327/0x530 net/can/j1939/transport.c:1410 j1939_tp_cmd_recv net/can/j1939/transport.c:2099 [inline] j1939_tp_recv+0x88e/0x1050 net/can/j1939/transport.c:2144 j1939_can_recv+0x732/0xb20 net/can/j1939/main.c:112 deliver net/can/af_can.c:572 [inline] can_rcv_filter+0x359/0x7f0 net/can/af_can.c:606 can_receive+0x327/0x480 net/can/af_can.c:663 can_rcv+0x144/0x260 net/can/af_can.c:687 __netif_receive_skb_one_core net/core/dev.c:5534 [inline] __netif_receive_skb+0x2e0/0x6a0 net/core/dev.c:5648 process_backlog+0x385/0x760 net/core/dev.c:5976 __napi_poll+0xcb/0x490 net/core/dev.c:6576 napi_poll net/core/dev.c:6645 [inline] net_rx_action+0x78b/0x1010 net/core/dev.c:6778 __do_softirq+0x2bb/0x942 kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu+0xf1/0x1c0 kernel/softirq.c:632 irq_exit_rcu+0x9/0x30 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x97/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 lock_acquire+0x25a/0x530 kernel/locking/lockdep.c:5758 rcu_lock_acquire include/linux/rcupdate.h:298 [inline] rcu_read_lock include/linux/rcupdate.h:750 [inline] batadv_nc_process_nc_paths+0xd6/0x3a0 net/batman-adv/network-coding.c:687 batadv_nc_worker+0x42a/0x610 net/batman-adv/network-coding.c:728 process_one_work kernel/workqueue.c:2633 [inline] process_scheduled_works+0x913/0x1420 kernel/workqueue.c:2706 worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787 kthread+0x2ef/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242 -> #1 (&jsk->sk_session_queue_lock){+.-.}-{2:2}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] j1939_sk_queue_drop_all+0x3a/0x240 net/can/j1939/socket.c:139 j1939_sk_netdev_event_netdown+0xed/0x160 net/can/j1939/socket.c:1282 j1939_netdev_notify+0xe2/0x140 net/can/j1939/main.c:381 notifier_call_chain+0x18f/0x3b0 kernel/notifier.c:93 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8725 do_setlink+0xcb0/0x41c0 net/core/rtnetlink.c:2903 __rtnl_newlink net/core/rtnetlink.c:3701 [inline] rtnl_newlink+0x180b/0x20a0 net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6615 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 -> #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+0x18ca/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] j1939_sk_errqueue+0x96/0x150 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+0x103/0x470 net/can/j1939/transport.c:299 j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline] j1939_cancel_active_session+0x354/0x490 net/can/j1939/transport.c:2194 j1939_netdev_notify+0xda/0x140 net/can/j1939/main.c:380 notifier_call_chain+0x18f/0x3b0 kernel/notifier.c:93 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8725 do_setlink+0xcb0/0x41c0 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0x1117/0x20a0 net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6615 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 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.4/17065: #0: ffffffff8f362788 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8f362788 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x82c/0x1040 net/core/rtnetlink.c:6612 #1: ffff88801e661088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #1: ffff88801e661088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline] #1: ffff88801e661088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x47/0x490 net/can/j1939/transport.c:2183 stack backtrace: CPU: 1 PID: 17065 Comm: syz-executor.4 Not tainted 6.8.0-rc2-syzkaller-00055-g6764c317b6bb #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 check_noncircular+0x36a/0x4a0 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+0x18ca/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] j1939_sk_errqueue+0x96/0x150 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+0x103/0x470 net/can/j1939/transport.c:299 j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline] j1939_cancel_active_session+0x354/0x490 net/can/j1939/transport.c:2194 j1939_netdev_notify+0xda/0x140 net/can/j1939/main.c:380 notifier_call_chain+0x18f/0x3b0 kernel/notifier.c:93 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8725 do_setlink+0xcb0/0x41c0 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0x1117/0x20a0 net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6615 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f503987dda9 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:00007f503a63c0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f50399abf80 RCX: 00007f503987dda9 RDX: 0000000000000000 RSI: 0000000020006440 RDI: 0000000000000006 RBP: 00007f50398ca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f50399abf80 R15: 00007fff1ae19098