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 0, t=10502 jiffies, g=24013, q=78) task:kworker/u4:0 state:R running task stack:20832 pid: 9 ppid: 2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: 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+0xfd/0x4f0 kernel/locking/lockdep.c:5596 Code: 1f 81 0c 73 0d e8 83 69 08 00 84 c0 0f 84 b9 02 00 00 48 c7 c0 44 d2 e3 8d 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 dd 02 00 00 <83> 3d 60 53 81 0c 00 0f 84 3f 01 00 00 65 8b 05 0f fa 9f 7e 85 c0 RSP: 0018:ffffc90000ce7960 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81627eac RDX: 0000000000000000 RSI: ffffffff8ad88060 RDI: ffffffff8ad88020 RBP: ffffc90000ce7ac0 R08: dffffc0000000000 R09: fffffbfff1bc73d6 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200019cf34 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88803884c000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:269 rcu_read_lock include/linux/rcupdate.h:696 [inline] cond_resched_rcu+0xac/0x130 include/linux/sched.h:2080 ip_vs_conn_flush net/netfilter/ipvs/ip_vs_conn.c:1393 [inline] ip_vs_conn_net_cleanup+0x376/0x520 net/netfilter/ipvs/ip_vs_conn.c:1475 __ip_vs_cleanup_batch+0x70/0xf0 net/netfilter/ipvs/ip_vs_core.c:2455 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 rcu: rcu_preempt kthread starved for 10515 jiffies! g24013 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:26200 pid: 15 ppid: 2 flags:0x00004000 Call Trace: 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+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 7117 Comm: syz-executor.4 Not tainted 5.15.145-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1788 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline] __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: d1 7e f6 ff 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 2e 2a 3d f7 48 89 df e8 06 7e 3e f7 e8 51 28 61 f7 fb bf 01 00 00 00 66 ba 31 f7 65 8b 05 d7 f5 dc 75 85 c0 74 02 5b c3 e8 64 0d db RSP: 0018:ffffc90010b77bc0 EFLAGS: 00000282 RAX: 727f768548428200 RBX: ffff888076158940 RCX: ffffffff913c6f03 RDX: dffffc0000000000 RSI: ffffffff8a8b0f80 RDI: 0000000000000001 RBP: 0000000000000000 R08: ffffffff8186a260 R09: ffffed100ec2b129 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000021 R13: dffffc0000000000 R14: ffff888076158dd8 R15: ffff888076158940 spin_unlock_irq include/linux/spinlock.h:413 [inline] get_signal+0x13ee/0x14e0 kernel/signal.c:2892 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:172 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fd8330bdce7 Code: 14 25 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 RSP: 002b:00007fd83161e178 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007fd8331dd058 RCX: 00007fd8330bdce9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd8331dd058 RBP: 00007fd8331dd050 R08: 00007fd83161e6c0 R09: 00007fd83161e6c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8331dd05c R13: 000000000000006e R14: 00007ffcda839370 R15: 00007ffcda839458