rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4237/1:b..l
	(detected by 0, t=10502 jiffies, g=142665, q=207)
task:kworker/u4:14   state:R  running task     stack:19904 pid: 4237 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780
 irqentry_exit+0x53/0x80 kernel/entry/common.c:426
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5626
Code: 2b 00 74 08 4c 89 f7 e8 dc 59 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc900031ff8e0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff9200063ff28 RCX: 1ffff9200063fec8
RDX: dffffc0000000000 RSI: ffffffff8a8b1e80 RDI: ffffffff8ad87b40
RBP: ffffc900031ffa40 R08: dffffc0000000000 R09: fffffbfff1f79c21
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200063ff24
R13: dffffc0000000000 R14: ffffc900031ff940 R15: 0000000000000246
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:269
 rcu_read_lock include/linux/rcupdate.h:696 [inline]
 inet_twsk_purge+0x11e/0xa20 net/ipv4/inet_timewait_sock.c:268
 ops_exit_list net/core/net_namespace.c:174 [inline]
 cleanup_net+0x763/0xb60 net/core/net_namespace.c:596
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
rcu: rcu_preempt kthread starved for 10522 jiffies! g142665 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:26712 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884
 rcu_gp_fqs_loop+0x2af/0xf70 kernel/rcu/tree.c:1959
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2132
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 731 Comm: syz-executor.0 Not tainted 5.15.139-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:cpu_max_bits_warn include/linux/cpumask.h:108 [inline]
RIP: 0010:cpumask_check include/linux/cpumask.h:115 [inline]
RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:344 [inline]
RIP: 0010:cpu_online include/linux/cpumask.h:895 [inline]
RIP: 0010:trace_user_enter+0x29/0x1b0 include/trace/events/context_tracking.h:34
Code: 00 55 53 e8 89 46 d9 ff 0f 1f 44 00 00 e8 7f 46 d9 ff 65 8b 1d 00 38 5b 7e bf 07 00 00 00 89 de e8 cc 49 d9 ff 83 fb 07 77 61 <e8> 62 46 d9 ff 89 d8 c1 e8 06 48 8d 3c c5 a8 93 e3 8d be 08 00 00
RSP: 0018:ffffc9000be37ed8 EFLAGS: 00000097
RAX: 0000000000000002 RBX: 0000000000000001 RCX: 0000000000040000
RDX: ffff88801d2fd940 RSI: 0000000000000001 RDI: 0000000000000007
RBP: 0000000000000001 R08: ffffffff81a6dd64 R09: fffffbfff1bc7276
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88801d2fd940 R15: 0000000000000000
FS:  00007fe521a156c0(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000041 CR3: 0000000019de5000 CR4: 00000000003506e0
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __context_tracking_enter+0x57/0x90 kernel/context_tracking.c:81
 user_enter_irqoff include/linux/context_tracking.h:41 [inline]
 __exit_to_user_mode kernel/entry/common.c:130 [inline]
 syscall_exit_to_user_mode+0x1da/0x250 kernel/entry/common.c:303
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe523491267
Code: 0b e9 68 fe ff ff 48 83 c4 18 48 8d 3d f2 05 c5 00 5b 5d 41 5c 41 5d 41 5e 41 5f e9 b3 68 fd ff 0f 1f 00 b8 27 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 b8 66 00 00 00 0f 05 c3 0f 1f 84 00 00
RSP: 002b:00007fe521a14b08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027
RAX: 0000000000001373 RBX: 00007fe521a14c70 RCX: 00007fe523491267
RDX: 00007fe521a14b40 RSI: 00007fe521a14c70 RDI: 0000000000000021
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 000000000000000b R14: 00007fe5235b2f80 R15: 00007ffde5621128
 </TASK>
sched: RT throttling activated