INFO: task kworker/u4:9:5662 blocked for more than 144 seconds.
      Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:9    state:D stack:22352 pid:5662  tgid:5662  ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x17df/0x4a40 kernel/sched/core.c:6727
 __schedule_loop kernel/sched/core.c:6804 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6819
 schedule_timeout+0xb0/0x310 kernel/time/timer.c:2159
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 __flush_workqueue+0x730/0x1630 kernel/workqueue.c:3617
 drain_workqueue+0xc9/0x390 kernel/workqueue.c:3730
 destroy_workqueue+0xba/0xc40 kernel/workqueue.c:5319
 bond_destructor+0x4d/0x80 drivers/net/bonding/bond_main.c:5846
 netdev_run_todo+0xd4f/0xf40 net/core/dev.c:10581
 default_device_exit_batch+0x975/0x9f0 net/core/dev.c:11625
 ops_exit_list net/core/net_namespace.c:175 [inline]
 cleanup_net+0x775/0xb90 net/core/net_namespace.c:618
 process_one_work kernel/workqueue.c:3049 [inline]
 process_scheduled_works+0x913/0x14f0 kernel/workqueue.c:3125
 worker_thread+0xa60/0x1000 kernel/workqueue.c:3206
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
2 locks held by getty/4822:
 #0: ffff88802a43d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900031432f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201
3 locks held by kworker/u4:9/5662:
 #0: ffff888015acd948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3024 [inline]
 #0: ffff888015acd948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x14f0 kernel/workqueue.c:3125
 #1: ffffc9000e24fd20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3024 [inline]
 #1: ffffc9000e24fd20 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x14f0 kernel/workqueue.c:3125
 #2: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf5/0xb90 net/core/net_namespace.c:580
2 locks held by kworker/u4:7/10783:
 #0: ffff8880b943c758 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
 #1: ffff8880b9428988 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x441/0x770 kernel/sched/psi.c:988
3 locks held by syz-executor.1/13035:
1 lock held by syz-executor.1/13046:
1 lock held by syz-executor.1/13048:
1 lock held by syz-executor.1/13055:
1 lock held by syz-executor.1/13080:
 #0: ffffffff8e1360f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #0: ffffffff8e1360f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x39a/0x820 kernel/rcu/tree_exp.h:939
1 lock held by syz-executor.2/13130:

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 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:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xfb0/0xff0 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11015 Comm: syz-executor.2 Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:radix_tree_shrink lib/radix-tree.c:499 [inline]
RIP: 0010:delete_node+0x436/0x770 lib/radix-tree.c:554
Code: f6 4c 89 f5 48 83 e5 fd 48 83 c5 08 48 89 e8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 ef e8 b2 df 91 f6 48 c7 45 00 00 00 00 00 <eb> 05 e8 23 ea 2e f6 48 8b 6c 24 28 48 8b 44 24 08 42 80 3c 20 00
RSP: 0018:ffffc90005007660 EFLAGS: 00000046
RAX: 1ffff11010211211 RBX: ffff8880361e3150 RCX: ffff888020975a00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002
RBP: ffff888081089088 R08: ffffffff8b64e619 R09: 000000000000000e
R10: dffffc0000000000 R11: fffffbfff1f0b6e6 R12: dffffc0000000000
R13: ffff88804f597440 R14: ffff888081089082 R15: ffff8880361e3158
FS:  00005555574cb480(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6f80bad988 CR3: 0000000035e84000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 radix_tree_delete_item+0x2e0/0x3f0 lib/radix-tree.c:1430
 free_pid+0x1a6/0x280 kernel/pid.c:155
 __unhash_process kernel/exit.c:133 [inline]
 __exit_signal kernel/exit.c:202 [inline]
 release_task+0xdc3/0x1810 kernel/exit.c:259
 wait_task_zombie kernel/exit.c:1189 [inline]
 wait_consider_task+0x1a14/0x2e50 kernel/exit.c:1416
 do_wait_thread kernel/exit.c:1479 [inline]
 __do_wait+0x1b0/0x850 kernel/exit.c:1597
 do_wait+0x2d3/0x540 kernel/exit.c:1631
 kernel_wait4+0x2a7/0x3e0 kernel/exit.c:1790
 __do_sys_wait4 kernel/exit.c:1818 [inline]
 __se_sys_wait4 kernel/exit.c:1814 [inline]
 __x64_sys_wait4+0x134/0x1e0 kernel/exit.c:1814
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f988627a7d7
Code: 89 7c 24 10 48 89 4c 24 18 e8 d5 a3 02 00 4c 8b 54 24 18 8b 54 24 14 41 89 c0 48 8b 74 24 08 8b 7c 24 10 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 89 44 24 10 e8 25 a4 02 00 8b 44
RSP: 002b:00007fffd324dac0 EFLAGS: 00000293 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 0000000000000058 RCX: 00007f988627a7d7
RDX: 0000000040000000 RSI: 00007fffd324db4c RDI: 00000000ffffffff
RBP: 00007fffd324db4c R08: 0000000000000000 R09: 00007fffd32540b0
R10: 0000000000000000 R11: 0000000000000293 R12: 00005555574cc95b
R13: 00005555574cc900 R14: 00007f98862dd5e0 R15: 000000000000000b
 </TASK>