rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P154/1:b..l
	(detected by 1, t=10502 jiffies, g=6233, q=235)
task:kworker/u4:2    state:R  running task     stack:25760 pid:  154 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc90002017900 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: f3992a326c5c2d00
RDX: 0000000000000000 RSI: ffffffff8a0b2860 RDI: ffffffff8a599340
RBP: ffffc90002017a20 R08: dffffc0000000000 R09: fffffbfff1ff6e19
R10: fffffbfff1ff6e19 R11: 1ffffffff1ff6e18 R12: ffffffff8c11c360
R13: 1ffff92000402f2c R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 inet_twsk_purge+0x119/0x810 net/ipv4/inet_timewait_sock.c:268
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x77b/0xb80 net/core/net_namespace.c:635
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 10526 jiffies! g6233 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:27464 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4451 Comm: syz.3.57 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:lockdep_hardirqs_on_prepare+0x79/0x760 kernel/locking/lockdep.c:4232
Code: 20 48 c1 eb 03 48 b8 f1 f1 f1 f1 00 f3 f3 f3 48 89 04 13 48 c7 c0 44 a2 69 8d 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 2a 05 00 00 <83> 3d 64 e0 0d 0c 00 0f 84 97 03 00 00 65 8b 05 db ad a6 7e a9 00
RSP: 0018:ffffc900034bfb40 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 1ffff92000697f6c RCX: 0000000000080000
RDX: dffffc0000000000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc900034bfc00 R08: dffffc0000000000 R09: ffffed1027fd4481
R10: ffffed1027fd4481 R11: 1ffff11027fd4480 R12: ffffffff812ba6a5
R13: 1ffff92000697fff R14: dffffc0000000000 R15: 1ffff92000697f84
FS:  00007f134c91e6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb2cfa1000 CR3: 000000001f39c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 trace_hardirqs_on+0x67/0x80 kernel/trace/trace_preemptirq.c:49
 __local_bh_enable_ip+0x12a/0x1b0 kernel/softirq.c:406
 handle_signal arch/x86/kernel/signal.c:840 [inline]
 arch_do_signal_or_restart+0xf18/0x1300 arch/x86/kernel/signal.c:869
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f134e5759b0
Code: 44 24 20 0f 29 44 24 30 0f 29 44 24 40 48 8b 44 24 08 ff d0 48 83 c4 50 31 c0 5b 5d 41 5c 41 5d 41 5e c3 0f 1f 80 00 00 00 00 <c3> 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 c3 66 66 2e 0f 1f
RSP: 002b:00007f134c91db38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f134e8ddfa8 RCX: 00007f134e6b6be9
RDX: 00007f134c91db40 RSI: 00007f134c91dc70 RDI: 0000000000000011
RBP: 00007f134e8ddfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f134e8de038 R14: 00007ffe06733060 R15: 00007ffe06733148
 </TASK>