rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9956/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=108781, q=169 ncpus=2)
task:kworker/u8:7    state:R  running task     stack:20520 pid:9956  tgid:9956  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: tipc_send tipc_conn_send_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x169e/0x54f0 kernel/sched/core.c:7188
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
 irqentry_exit+0x14f/0x730 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5874
Code: ff ff ff e8 b1 f2 95 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 8b ed d5 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 28 fc ef
RSP: 0018:ffffc90004027740 EFLAGS: 00000282
RAX: 8a822f83744cf600 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 0000000000000003 RSI: ffffffff8d8b3bc3 RDI: ffffffff8ba84960
RBP: ffffffff8ad5b23a R08: ffffc90004027560 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff81a0ded0 R12: 0000000000000000
R13: ffff888039d848f0 R14: 0000000000000001 R15: 0000000000000246
 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56
 spin_lock_bh include/linux/spinlock_rt.h:90 [inline]
 tipc_conn_kref_release net/tipc/topsrv.c:130 [inline]
 kref_put include/linux/kref.h:65 [inline]
 conn_put+0x8a/0x380 net/tipc/topsrv.c:148
 tipc_conn_send_work+0xa17/0xaa0 net/tipc/topsrv.c:308
 process_one_work+0x9a3/0x1710 kernel/workqueue.c:3312
 process_scheduled_works kernel/workqueue.c:3403 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3489
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>