INFO: task kworker/u8:3:52 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc7-syzkaller-00014-gd608703fcdd9 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3    state:D stack:22376 pid:52    tgid:52    ppid:2      task_flags:0x4208160 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 afs_cell_purge+0x3d9/0x540 fs/afs/cell.c:893
 afs_net_exit+0x50/0x100 fs/afs/main.c:146
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x71a/0xbd0 net/core/net_namespace.c:654
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
3 locks held by kworker/u8:3/52:
 #0: ffff88801aef3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801aef3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc90000bd7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000bd7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
 #2: ffffffff8f2dba50 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x145/0xbd0 net/core/net_namespace.c:608
2 locks held by kworker/u8:4/67:
 #0: ffff8880b88399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605
 #1: ffff8880b8923b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987
2 locks held by getty/5577:
 #0: ffff88814dd900a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000363c2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/u8:9/9148:
2 locks held by syz-executor/10464:
 #0: ffff888062a560e0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff888062a560e0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff888062a560e0 (&type->s_umount_key#59){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffffffff8df43880 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3774
2 locks held by syz-executor/10809:
 #0: ffff8880621f80e0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880621f80e0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880621f80e0 (&type->s_umount_key#59){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffffffff8df43880 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3774
2 locks held by syz.4.523/11225:
2 locks held by rm/11254:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc7-syzkaller-00014-gd608703fcdd9 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:437
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 11225 Comm: syz.4.523 Not tainted 6.15.0-rc7-syzkaller-00014-gd608703fcdd9 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:get_dep_list kernel/locking/lockdep.c:1571 [inline]
RIP: 0010:__bfs_next kernel/locking/lockdep.c:1703 [inline]
RIP: 0010:__bfs kernel/locking/lockdep.c:1753 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1861 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2832 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3170 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3285 [inline]
RIP: 0010:validate_chain+0xe11/0x2140 kernel/locking/lockdep.c:3909
Code: 00 48 89 05 b1 a8 dc 13 48 8d 84 24 88 00 00 00 48 89 05 a2 28 dc 13 31 f6 45 31 ed 4d 85 ed 74 2f 49 8b 45 30 48 85 c0 74 26 <48> 8b 40 10 48 83 c0 30 49 8b 4d 00 48 89 8c 24 d0 00 00 00 48 39
RSP: 0018:ffffc900039ff4e8 EFLAGS: 00000082
RAX: ffffffff96076108 RBX: 00000000000003fd RCX: 00000000000502cd
RDX: 0000000000000008 RSI: 00000000000003fd RDI: ffff88802bbbbc00
RBP: ffffffff932048b8 R08: ffffc900039ff4b0 R09: 0000000000000020
R10: 0000000000000000 R11: ffffffff819eafe0 R12: ffffffff96094018
R13: ffffffff96108fb8 R14: ffff88802bbbc740 R15: 0000000000000382
FS:  00007f72054d26c0(0000) GS:ffff8881260f6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fda70e4043c CR3: 00000000626dc000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __lock_acquire+0xaac/0xd20 kernel/locking/lockdep.c:5235
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
 debug_object_activate+0xbb/0x420 lib/debugobjects.c:818
 debug_timer_activate kernel/time/timer.c:835 [inline]
 __mod_timer+0xa4f/0xf30 kernel/time/timer.c:1166
 queue_delayed_work_on+0x18b/0x280 kernel/workqueue.c:2561
 queue_delayed_work include/linux/workqueue.h:677 [inline]
 fbcon_add_cursor_work drivers/video/fbdev/core/fbcon.c:405 [inline]
 fbcon_cursor+0x34d/0x5a0 drivers/video/fbdev/core/fbcon.c:1337
 hide_cursor+0xd5/0x480 drivers/tty/vt/vt.c:846
 update_region+0x1c1/0x490 drivers/tty/vt/vt.c:632
 vcs_write+0xd65/0x1260 drivers/tty/vt/vc_screen.c:698
 vfs_write+0x27e/0xa90 fs/read_write.c:682
 ksys_write+0x145/0x250 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f720458e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f72054d2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f72047b5fa0 RCX: 00007f720458e969
RDX: 0000000000000020 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007f7204610ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f72047b5fa0 R15: 00007ffd60772238
 </TASK>