rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11101/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=55669, q=536 ncpus=2)
task:kworker/0:0     state:R  running task     stack:21360 pid:11101 tgid:11101 ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: events_long defense_work_handler
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6765
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7087
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:240
Code: 48 8b 05 43 ef 49 7e 48 8b 80 20 16 00 00 c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <49> 89 d2 49 89 f8 49 89 f1 65 48 8b 15 0f ef 49 7e 65 8b 05 10 ef
RSP: 0018:ffffc9000307fbf0 EFLAGS: 00000202

RAX: 0000000000000000 RBX: 0000000000000080 RCX: ffffffff89b26228
RDX: 0000000000000028 RSI: 0000000000000080 RDI: 0000000000000004
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000002 R12: ffff88805dc5a000
R13: 0000000000000028 R14: 1ffffffff1bc2040 R15: ffff88801b091000
 ip_vs_random_dropentry+0x4b8/0xf20 net/netfilter/ipvs/ip_vs_conn.c:1316
 defense_work_handler+0xb6/0xd0 net/netfilter/ipvs/ip_vs_ctl.c:237
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>