rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9/1:b..l
	(detected by 1, t=10502 jiffies, g=12937, q=149)
task:kworker/u4:0    state:R  running task     stack:23920 pid:    9 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 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:debug_lockdep_rcu_enabled+0x12/0x30 kernel/rcu/update.c:280
Code: 2b 8a e8 f1 0a f5 ff 0f 0b eb d1 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 31 c0 83 3d bb ae cd 03 00 74 1d 83 3d 32 e1 cd 03 00 <74> 14 65 48 8b 0d 24 41 46 76 31 c0 83 b9 ec 0a 00 00 00 0f 94 c0
RSP: 0018:ffffc90000ce7a38 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff966cd260 RCX: 7ddc397fdcfd9d00
RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f800
RBP: ffffc90000ce7b50 R08: dffffc0000000000 R09: 1ffffffff203a618
R10: dffffc0000000000 R11: fffffbfff203a619 R12: 0000000000017ffa
R13: dffffc0000000000 R14: ffff88802c8bffd8 R15: ffffffff8d617440
 rcu_read_lock include/linux/rcupdate.h:741 [inline]
 inet_twsk_purge+0x11e/0x840 net/ipv4/inet_timewait_sock.c:268
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x791/0xba0 net/core/net_namespace.c:635
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 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 10455 jiffies! g12937 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:26960 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 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: 5067 Comm: syz.4.205 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:226 [inline]
RIP: 0010:__sanitizer_cov_trace_cmp8+0x4/0x80 kernel/kcov.c:273
Code: 77 22 89 ff 89 f6 4a c7 44 02 08 04 00 00 00 4a 89 7c 02 10 4a 89 74 02 18 4a 89 44 02 20 48 ff c1 48 89 0a c3 90 48 8b 04 24 <65> 48 8b 0d 94 4b 89 7e 65 8b 15 95 4b 89 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc9000153faa8 EFLAGS: 00000046
RAX: ffffffff8168aa17 RBX: ffff88805b506518 RCX: 0000000000080000
RDX: ffffc90005d31000 RSI: 189658df8938e422 RDI: 189658df893944f8
RBP: 189658df893944f8 R08: ffffffff8d89dc2f R09: 1ffffffff1b13b85
R10: dffffc0000000000 R11: fffffbfff1b13b86 R12: 00000000000060d6
R13: 189658df8938e422 R14: 1ffff1100b6a0ca6 R15: ffff88805b506530
FS:  00007fd2093a76c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd209386d58 CR3: 000000005d169000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 hrtimer_forward+0xf7/0x290 kernel/time/hrtimer.c:-1
 common_hrtimer_rearm+0x8c/0x110 kernel/time/posix-timers.c:303
 posixtimer_rearm+0x131/0x340 kernel/time/posix-timers.c:329
 dequeue_signal+0x174/0x440 kernel/signal.c:696
 get_signal+0x6fe/0x12c0 kernel/signal.c:2781
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 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+0xee/0x180 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: 0033:0x7fd20b14d627
Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89
RSP: 002b:00007fd2093a7028 EFLAGS: 00000246
RAX: 0000000000000049 RBX: 00007fd20b3c6fa0 RCX: 00007fd20b14d629
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004
RBP: 00007fd20b1e3b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd20b3c7038 R14: 00007fd20b3c6fa0 R15: 00007ffe47c9a9d8
 </TASK>