------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 1122 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 1122 Comm: kworker/u8:7 Not tainted 6.11.0-rc3-next-20240816-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue:  cleanup_net
RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Code: a0 62 60 8c e8 27 7f a2 fc 90 0f 0b 90 90 eb 99 e8 6b 66 e0 fc c6 05 d8 69 4f 0b 01 90 48 c7 c7 00 63 60 8c e8 07 7f a2 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 48 66 e0 fc c6 05 b2 69 4f 0b 01 90
RSP: 0000:ffffc900000076e0 EFLAGS: 00010246
RAX: bfb9d1dccaa67e00 RBX: ffff88802a087224 RCX: ffff888022b9bc00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff8155aeb2 R09: fffffbfff1cfa34c
R10: dffffc0000000000 R11: fffffbfff1cfa34c R12: ffff88801fe0d800
R13: ffff88802a087224 R14: ffff88801fe0d800 R15: ffff88805dff8618
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6ffa3706d3 CR3: 0000000068ee0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 kfree_skb_reason include/linux/skbuff.h:1260 [inline]
 kfree_skb include/linux/skbuff.h:1269 [inline]
 j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline]
 j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline]
 j1939_xtp_rx_cts+0x552/0xc70 net/can/j1939/transport.c:1484
 j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline]
 j1939_tp_recv+0x8ae/0x1050 net/can/j1939/transport.c:2161
 j1939_can_recv+0x732/0xb20 net/can/j1939/main.c:108
 deliver net/can/af_can.c:572 [inline]
 can_rcv_filter+0x359/0x7f0 net/can/af_can.c:606
 can_receive+0x31c/0x470 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:5661 [inline]
 __netif_receive_skb+0x2e0/0x650 net/core/dev.c:5775
 process_backlog+0x662/0x15b0 net/core/dev.c:6108
 __napi_poll+0xcb/0x490 net/core/dev.c:6772
 napi_poll net/core/dev.c:6841 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:6963
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 do_softirq+0x11b/0x1e0 kernel/softirq.c:455
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
 pppoe_flush_dev drivers/net/ppp/pppoe.c:327 [inline]
 pppoe_device_event+0x483/0x4b0 drivers/net/ppp/pppoe.c:346
 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2032 [inline]
 call_netdevice_notifiers net/core/dev.c:2046 [inline]
 __dev_close_many+0x146/0x300 net/core/dev.c:1532
 dev_close_many+0x24e/0x4c0 net/core/dev.c:1583
 unregister_netdevice_many_notify+0x50b/0x1c40 net/core/dev.c:11327
 unregister_netdevice_many net/core/dev.c:11414 [inline]
 unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11289
 unregister_netdevice include/linux/netdevice.h:3097 [inline]
 nsim_destroy+0x180/0x5c0 drivers/net/netdevsim/netdev.c:778
 __nsim_dev_port_del+0x14b/0x1b0 drivers/net/netdevsim/dev.c:1425
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1437 [inline]
 nsim_dev_reload_destroy+0x28a/0x490 drivers/net/netdevsim/dev.c:1658
 nsim_dev_reload_down+0x98/0xd0 drivers/net/netdevsim/dev.c:965
 devlink_reload+0x18b/0x870 net/devlink/dev.c:461
 devlink_pernet_pre_exit+0x1f3/0x440 net/devlink/core.c:509
 ops_pre_exit_list net/core/net_namespace.c:163 [inline]
 cleanup_net+0x615/0xcc0 net/core/net_namespace.c:606
 process_one_work kernel/workqueue.c:3232 [inline]
 process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3313
 worker_thread+0x86d/0xd10 kernel/workqueue.c:3390
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>