INFO: task syz-executor.2:15851 blocked for more than 143 seconds.
      Not tainted 6.3.0-rc7-syzkaller-02415-gc248b27cfc0a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:23296 pid:15851 ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5307 [inline]
 __schedule+0xc91/0x5770 kernel/sched/core.c:6625
 schedule+0xde/0x1a0 kernel/sched/core.c:6701
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6760
 rwsem_down_write_slowpath+0x3e2/0x1220 kernel/locking/rwsem.c:1178
 __down_write_common kernel/locking/rwsem.c:1306 [inline]
 __down_write kernel/locking/rwsem.c:1315 [inline]
 down_write+0x1d2/0x200 kernel/locking/rwsem.c:1574
 unregister_netdevice_notifier+0x22/0x180 net/core/dev.c:1757
 devlink_free+0x2cb/0x460 net/devlink/core.c:269
 nsim_drv_remove+0x158/0x1d0 drivers/net/netdevsim/dev.c:1687
 device_remove+0xc8/0x170 drivers/base/dd.c:540
 __device_release_driver drivers/base/dd.c:1240 [inline]
 device_release_driver_internal+0x443/0x610 drivers/base/dd.c:1263
 bus_remove_device+0x22c/0x420 drivers/base/bus.c:574
 device_del+0x48a/0xb80 drivers/base/core.c:3775
 device_unregister+0x1e/0xc0 drivers/base/core.c:3805
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:310 [inline]
 del_device_store+0x34e/0x4a0 drivers/net/netdevsim/bus.c:219
 bus_attr_store+0x76/0xa0 drivers/base/bus.c:170
 sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x3f1/0x600 fs/kernfs/file.c:334
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x9f6/0xe20 fs/read_write.c:584
 ksys_write+0x12b/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: 0033:0x7f296a83deef
RSP: 002b:00007ffda9669530 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f296a83deef
RDX: 0000000000000001 RSI: 00007ffda9669580 RDI: 0000000000000005
RBP: 0000000000000005 R08: 0000000000000000 R09: 00007ffda96694d0
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f296a8e78b6
R13: 00007ffda9669580 R14: 0000000000000000 R15: 00007ffda9669c50
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
 #0: ffff8880b983c298 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2f/0x120 kernel/sched/core.c:539
 #1: ffff8880b9828808 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2de/0x950 kernel/sched/psi.c:976
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c794a70 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:510
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8c794770 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:510
1 lock held by khungtaskd/28:
 #0: ffffffff8c7955c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6495
4 locks held by kworker/u4:4/56:
2 locks held by getty/4740:
 #0: ffff88814a37f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x26/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffffc900015902f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef4/0x13e0 drivers/tty/n_tty.c:2177
6 locks held by syz-executor.2/15851:
 #0: ffff88802b9dc460 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12b/0x250 fs/read_write.c:637
 #1: ffff88805cccc488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x285/0x600 fs/kernfs/file.c:325
 #2: ffff8880203382c0 (kn->active#51){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2a9/0x600 fs/kernfs/file.c:326
 #3: ffffffff8d7e65a8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xc9/0x4a0 drivers/net/netdevsim/bus.c:209
 #4: ffff88805ad190e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:832 [inline]
 #4: ffff88805ad190e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1063 [inline]
 #4: ffff88805ad190e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa4/0x610 drivers/base/dd.c:1260
 #5: ffffffff8e0e9450 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x22/0x180 net/core/dev.c:1757
1 lock held by syz-executor.2/15912:
 #0: ffffffff8e0e9450 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4cb/0x8e0 net/core/net_namespace.c:486

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.3.0-rc7-syzkaller-02415-gc248b27cfc0a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x29c/0x350 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x2a4/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xe16/0x1090 kernel/hung_task.c:379
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 56 Comm: kworker/u4:4 Not tainted 6.3.0-rc7-syzkaller-02415-gc248b27cfc0a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Workqueue: netns cleanup_net
RIP: 0010:__sanitizer_cov_trace_pc+0x60/0x70 kernel/kcov.c:225
Code: 82 40 15 00 00 83 f8 02 75 20 48 8b 8a 48 15 00 00 8b 92 44 15 00 00 48 8b 01 48 83 c0 01 48 39 c2 76 07 48 89 01 48 89 34 c1 <c3> 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 55 41 54 49 89
RSP: 0018:ffffc90001577ab0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000040000 RCX: 0000000000000000
RDX: ffff888017333a80 RSI: ffffffff8847aa97 RDI: 0000000000000004
RBP: dffffc0000000000 R08: 0000000000000004 R09: 0000000000011eef
R10: 0000000000040000 R11: 0000000000000000 R12: ffffc90001577b90
R13: 0000000000011eef R14: 0000000000000001 R15: 000000000000d7c0
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056445b5d8838 CR3: 000000002a759000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 get_next_corpse net/netfilter/nf_conntrack_core.c:2366 [inline]
 nf_ct_iterate_cleanup+0xa7/0x500 net/netfilter/nf_conntrack_core.c:2419
 nf_ct_iterate_cleanup_net+0xdb/0x110 net/netfilter/nf_conntrack_core.c:2440
 nf_conntrack_cleanup_net_list+0x1cc/0x5d0 net/netfilter/nf_conntrack_core.c:2553
 ops_exit_list+0x125/0x170 net/core/net_namespace.c:174
 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613
 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390
 worker_thread+0x669/0x1090 kernel/workqueue.c:2537
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>