INFO: task syz-executor:18774 blocked for more than 145 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:24712 pid:18774 tgid:18774 ppid:1      task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6908
 __schedule_loop kernel/sched/core.c:6990 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7005
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7062
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:688
 ksys_write+0x12a/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb0bf55cfce
RSP: 002b:00007ffe5ff4e878 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00005555729d3500 RCX: 00007fb0bf55cfce
RDX: 0000000000000001 RSI: 00007ffe5ff4e900 RDI: 0000000000000005
RBP: 00007fb0bf63345c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe5ff4e900 R14: 00007fb0c0344620 R15: 0000000000000003
 </TASK>
INFO: task syz-executor:19213 blocked for more than 146 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:24872 pid:19213 tgid:19213 ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6908
 __schedule_loop kernel/sched/core.c:6990 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7005
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7062
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:688
 ksys_write+0x12a/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fec4035cfce
RSP: 002b:00007ffc7b469558 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555574b81500 RCX: 00007fec4035cfce
RDX: 0000000000000001 RSI: 00007ffc7b4695e0 RDI: 0000000000000005
RBP: 00007fec4043345c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc7b4695e0 R14: 00007fec41144620 R15: 0000000000000003
 </TASK>
INFO: task syz-executor:19224 blocked for more than 147 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:24504 pid:19224 tgid:19224 ppid:19223  task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6908
 __schedule_loop kernel/sched/core.c:6990 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7005
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7062
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:688
 ksys_write+0x12a/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb9de95cfce
RSP: 002b:00007ffca6f48568 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555562bd0500 RCX: 00007fb9de95cfce
RDX: 0000000000000001 RSI: 00007ffca6f485f0 RDI: 0000000000000005
RBP: 00007fb9dea3345c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffca6f485f0 R14: 00007fb9df744620 R15: 0000000000000003
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by dhcpcd/5471:
 #0: ffffffff905e0e88 (vlan_ioctl_mutex){+.+.}-{4:4}, at: sock_ioctl+0x5ca/0x6b0 net/socket.c:1337
 #1: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: vlan_ioctl_handler+0xcf/0xa70 net/8021q/vlan.c:579
2 locks held by getty/5573:
 #0: ffff8880331150a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock
){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
4 locks held by kworker/0:4/5877:
12 locks held by kworker/u8:12/6170:
3 locks held by kworker/u8:19/6178:
 #0: ffff88813fe9c148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250
 #1: ffffc90005b6fd08 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251
 #2: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:313
3 locks held by kworker/u8:20/6179:
 #0: ffff888032b09948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250
 #1: 
ffffc90005b7fd08 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251
 #2: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4738
4 locks held by kworker/u8:3/3958:
 #0: ffff88802bb20148 ((wq_completion)wg-kex-wg0#11){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250
 #1: ffffc9000217fd08 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251
 #2: ffff8880292ad348 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0xec/0x610 drivers/net/wireguard/noise.c:529
 #3: ffff8880574a7030
 (
&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x100/0x610 drivers/net/wireguard/noise.c:530
4 locks held by kworker/u8:6/15222:
 #0: ffff88801cac9148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250
 #1: 
ffffc90003207d08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251
 #2: ffffffff905f82f0 (pernet_ops_rwsem
){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:675
 #3: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1b/0x250 drivers/net/wireguard/device.c:419
4 locks held by syz-executor/18774:
 #0: ffff888035040420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740
 #1: 
ffff88804f4db088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343
 #2: ffff888029d322d8 (kn->active#52){.+.+}-{0:0}
, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344
 #3: ffffffff8fb69488 (nsim_bus_dev_list_lock){+.+.}-{4:4}
, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
8 locks held by syz-executor/18954:
 #0: 
ffff888035040420
 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740
 #1: ffff88803e4f5488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343
 #2: ffff888029d322d8 (kn->active
#52){.+.+}-{0:0}
, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344
 #3: ffffffff8fb69488 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
 #4: ffff888057b3e0e8 (&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1106 [inline]
){....}-{4:4}, at: device_release_driver_internal+0xaa/0x600 drivers/base/dd.c:1304
 #5: ffff888057b3f250 (&devlink->lock_key#69){+.+.}-{4:4}, at: nsim_drv_remove+0x4a/0x1e0 drivers/net/netdevsim/dev.c:1778
 #6: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x108/0x830 drivers/net/netdevsim/netdev.c:1177
 #7: ffffffff8e680c50
 (cpu_hotplug_lock){++++}-{0:0}, at: flush_all_backlogs net/core/dev.c:6541 [inline]
 (cpu_hotplug_lock){++++}-{0:0}, at: unregister_netdevice_many_notify+0x953/0x2580 net/core/dev.c:12391
4 locks held by syz-executor/19213:
 #0: ffff888035040420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740
 #1: ffff888055c3e088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343
 #2: ffff888029d322d8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888029d322d8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344
 #3: ffffffff8fb69488 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/19224:
 #0: ffff888035040420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740
 #1: ffff8880b1fc3888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343
 #2: ffff888029d322d8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888029d322d8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344
 #3: ffffffff8fb69488 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
2 locks held by syz-executor/20209:
 #0: ffffffff8f981688 (&ops->srcu#2){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
 #0: ffffffff8f981688 (&ops->srcu#2){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
 #0: ffffffff8f981688 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x113/0x2c0 net/core/rtnetlink.c:574
 #1: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8bb/0x2380 net/core/rtnetlink.c:4071
1 lock held by syz-executor/20776:
 #0: ffffffff90610c28
 (
rtnl_mutex){+.+.}-{4:4}
, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
, at: inet_rtm_newaddr+0x30c/0x18b0 net/ipv4/devinet.c:978
2 locks held by syz-executor/20777:
 #0: ffffffff905f82f0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:577
 #1: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: register_nexthop_notifier+0x1b/0x70 net/ipv4/nexthop.c:3968

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xd25/0x1050 kernel/hung_task.c:515
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
lapbether: lapb_data_request error - 4
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6170 Comm: kworker/u8:12 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound macvlan_process_broadcast
RIP: 0010:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:401
Code: 5c 8f fc 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c e9 cd b4 19 06 e8 78 d8 fb fc eb a2 e8 01 d9
RSP: 0018:ffffc90000007340 EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff857956e0 RDI: ffffffff9b4a09c0
RBP: ffffffff9b4a0980 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000020 R14: fffffbfff369418a R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888124345000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa472d99e7d CR3: 0000000032f73000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 serial_in drivers/tty/serial/8250/8250.h:128 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
 wait_for_lsr+0x13a/0x210 drivers/tty/serial/8250/8250_port.c:1961
 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline]
 serial8250_console_write+0xdb9/0x1900 drivers/tty/serial/8250/8250_port.c:3342
 console_emit_next_record kernel/printk/printk.c:3183 [inline]
 console_flush_one_record+0x790/0xe50 kernel/printk/printk.c:3269
 console_flush_all kernel/printk/printk.c:3343 [inline]
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0x103/0x260 kernel/printk/printk.c:3413
 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
 _printk+0xcf/0x110 kernel/printk/printk.c:2504
 lapbeth_xmit.cold+0x45/0x4a drivers/net/wan/lapbether.c:226
 __netdev_start_xmit include/linux/netdevice.h:5275 [inline]
 netdev_start_xmit include/linux/netdevice.h:5284 [inline]
 xmit_one net/core/dev.c:3871 [inline]
 dev_hard_start_xmit+0x121/0x7d0 net/core/dev.c:3887
 __dev_queue_xmit+0x32c1/0x4800 net/core/dev.c:4840
 dev_queue_xmit include/linux/netdevice.h:3384 [inline]
 x25_send_frame+0x20e/0x2a0 net/x25/x25_dev.c:193
 x25_transmit_restart_request+0x1fd/0x270 net/x25/x25_link.c:153
 x25_link_control+0xa3/0x4a0 net/x25/x25_link.c:102
 x25_receive_data net/x25/x25_dev.c:43 [inline]
 x25_lapb_receive_frame+0x514/0xfc0 net/x25/x25_dev.c:127
 __netif_receive_skb_one_core+0x1b2/0x1e0 net/core/dev.c:6167
 netif_receive_skb_core+0x5a/0x1a0 net/core/dev.c:6192
 lapbeth_napi_poll+0x42/0xc0 drivers/net/wan/lapbether.c:100
 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7695
 napi_poll net/core/dev.c:7758 [inline]
 net_rx_action+0xa40/0xf20 net/core/dev.c:7910
 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622
 do_softirq kernel/softirq.c:523 [inline]
 do_softirq+0xac/0xe0 kernel/softirq.c:510
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 netif_rx net/core/dev.c:5733 [inline]
 netif_rx+0x93/0xb0 net/core/dev.c:5722
 macvlan_broadcast+0x37d/0x680 drivers/net/macvlan.c:292
 macvlan_multicast_rx drivers/net/macvlan.c:304 [inline]
 macvlan_multicast_rx+0xe0/0x110 drivers/net/macvlan.c:298
 macvlan_process_broadcast+0x3e4/0x690 drivers/net/macvlan.c:340
 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275
 process_scheduled_works kernel/workqueue.c:3358 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3439
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>