INFO: task syz.3.490:7891 blocked for more than 143 seconds.
      Not tainted 6.12.0-next-20241119-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.490       state:D stack:23568 pid:7891  tgid:7891  ppid:5827   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905
 __mutex_lock_common kernel/locking/mutex.c:665 [inline]
 __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735
 bdev_release+0x17e/0x700 block/bdev.c:1087
 blkdev_release+0x15/0x20 block/fops.c:635
 __fput+0x23c/0xa50 fs/file_table.c:450
 task_work_run+0x24f/0x310 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3b7277e759
RSP: 002b:00007ffd09904118 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f3b72937a80 RCX: 00007f3b7277e759
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f3b72937a80 R08: 0000000000000006 R09: 00007ffd0990440f
R10: 00000000005ebc60 R11: 0000000000000246 R12: 000000000003638a
R13: 00007ffd09904220 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
4 locks held by kworker/u8:7/3417:
 #0: ffff88801baed948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801baed948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc9000bebfd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000bebfd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fc94610 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:586
 #3: ffff8880b863e8d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb0/0x140 kernel/sched/core.c:606
2 locks held by getty/5586:
 #0: ffff88814cec50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900033132f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
1 lock held by udevd/5993:
 #0: ffff88802581f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xf0/0xc50 block/bdev.c:904
1 lock held by syz-executor/7075:
 #0: ffffffff8e93cff8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
 #0: ffffffff8e93cff8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976
1 lock held by syz.3.490/7891:
 #0: ffff88802581f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x17e/0x700 block/bdev.c:1087
1 lock held by syz.3.490/7897:
 #0: ffff88802581f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_fput+0xe6/0x2f0 block/bdev.c:1128
3 locks held by syz-executor/8058:
 #0: ffff8880640c4d80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:481 [inline]
 #0: ffff8880640c4d80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x203/0x510 net/bluetooth/hci_core.c:2698
 #1: ffff8880640c4078 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x5c8/0x11c0 net/bluetooth/hci_sync.c:5200
 #2: ffffffff8fe013e8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2047 [inline]
 #2: ffffffff8fe013e8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa6/0x240 net/bluetooth/hci_conn.c:2698
5 locks held by kworker/u8:12/8385:
1 lock held by syz-executor/9479:
 #0: ffffffff8fc94610 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x328/0x570 net/core/net_namespace.c:496

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-next-20241119-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline]
 watchdog+0xffb/0x1040 kernel/hung_task.c:397
 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>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3 Comm: pool_workqueue_ Not tainted 6.12.0-next-20241119-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:remove_class_from_lock_chain kernel/locking/lockdep.c:6178 [inline]
RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:6217 [inline]
RIP: 0010:zap_class+0x165/0x840 kernel/locking/lockdep.c:6259
Code: 8b 3b eb 03 4d 8b 3f 4d 85 ff 74 bc 49 83 c7 f8 74 b6 4d 89 fd 49 c1 ed 03 43 0f b6 44 35 00 84 c0 0f 85 2d 02 00 00 41 8b 1f <f6> c3 fc 0f 84 fe 01 00 00 48 c1 eb 08 81 fb 00 00 50 00 73 7b 48
RSP: 0018:ffffc90000087c68 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000003bf3710 RCX: 000000000004a0de
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff9425d3b8
RBP: ffffffff932568fe R08: ffffffff9425d3bf R09: 1ffffffff284ba77
R10: dffffc0000000000 R11: fffffbfff284ba78 R12: 0000000000000e5f
R13: 1ffffffff288750c R14: dffffc0000000000 R15: ffffffff9443a860
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055757c034088 CR3: 000000006f5d4000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __lockdep_free_key_range kernel/locking/lockdep.c:6385 [inline]
 lockdep_unregister_key+0x3d2/0x610 kernel/locking/lockdep.c:6587
 wq_unregister_lockdep kernel/workqueue.c:4803 [inline]
 pwq_release_workfn+0x6d1/0x800 kernel/workqueue.c:5099
 kthread_worker_fn+0x500/0xb70 kernel/kthread.c:844
 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>