netlink: 'syz-executor.0': attribute type 27 has an invalid length. ====================================================== WARNING: possible circular locking dependency detected 6.8.0-rc1-syzkaller-00385-g4854cf9c61d0 #0 Not tainted ------------------------------------------------------ syz-executor.0/15384 is trying to acquire lock: ffff88802e1c90d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff88802e1c90d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_errqueue+0x96/0x150 net/can/j1939/socket.c:1083 but task is already holding lock: ffff88802e1c9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff88802e1c9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline] ffff88802e1c9088 (&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+0x26c/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+0x323/0x530 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+0x349/0x7c0 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+0x1ca/0x530 net/core/dev.c:5648 process_backlog+0x385/0x760 net/core/dev.c:5976 __napi_poll+0xc7/0x480 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+0x2b8/0x939 kernel/softirq.c:553 do_softirq+0x11b/0x1e0 kernel/softirq.c:454 __local_bh_enable_ip+0x1b7/0x1f0 kernel/softirq.c:381 local_bh_enable include/linux/bottom_half.h:33 [inline] srcu_invoke_callbacks+0x241/0x490 kernel/rcu/srcutree.c:1740 process_one_work kernel/workqueue.c:2633 [inline] process_scheduled_works+0x90f/0x1420 kernel/workqueue.c:2706 worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787 kthread+0x2d3/0x370 kernel/kthread.c:388 ret_from_fork+0x48/0x80 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}: 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+0x18c/0x3b0 kernel/notifier.c:93 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8725 do_setlink+0xcc4/0x4200 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0x1114/0x2080 net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x882/0x1030 net/core/rtnetlink.c:6615 netlink_rcv_skb+0x1df/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7e6/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa37/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x592/0x890 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x230 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+0x1909/0x5ab0 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+0xff/0x460 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+0x18c/0x3b0 kernel/notifier.c:93 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8725 do_setlink+0xcc4/0x4200 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0x1114/0x2080 net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x882/0x1030 net/core/rtnetlink.c:6615 netlink_rcv_skb+0x1df/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7e6/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa37/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x592/0x890 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x230 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.0/15384: #0: ffffffff8eb496c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8eb496c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x82c/0x1030 net/core/rtnetlink.c:6612 #1: ffff88802e1c9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #1: ffff88802e1c9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline] #1: ffff88802e1c9088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x47/0x490 net/can/j1939/transport.c:2183 stack backtrace: CPU: 0 PID: 15384 Comm: syz-executor.0 Not tainted 6.8.0-rc1-syzkaller-00385-g4854cf9c61d0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 check_noncircular+0x366/0x490 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+0x1909/0x5ab0 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+0xff/0x460 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+0x18c/0x3b0 kernel/notifier.c:93 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8725 do_setlink+0xcc4/0x4200 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0x1114/0x2080 net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x882/0x1030 net/core/rtnetlink.c:6615 netlink_rcv_skb+0x1df/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7e6/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa37/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x592/0x890 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f16a927cda9 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:00007f16aa0250c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f16a93abf80 RCX: 00007f16a927cda9 RDX: 0000000000000000 RSI: 0000000020006440 RDI: 0000000000000006 RBP: 00007f16a92c947a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f16a93abf80 R15: 00007ffe44c6e018