rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4353/1:b..l
	(detected by 1, t=10502 jiffies, g=6849, q=398)
task:kworker/u4:9    state:R  running task     stack:25632 pid: 4353 ppid:     2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 preempt_schedule_irq+0xb1/0x150 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:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:344 [inline]
RIP: 0010:cpu_online include/linux/cpumask.h:895 [inline]
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline]
RIP: 0010:lock_acquire+0xa6/0x3f0 kernel/locking/lockdep.c:5594
Code: 3d 00 66 43 c7 44 3d 09 f3 f3 43 c6 44 3d 0b f3 0f 1f 44 00 00 65 44 8b 35 4f 1c a6 7e 41 83 fe 08 0f 83 8c 01 00 00 44 89 f0 <c1> e8 06 48 8d 3c c5 68 9a 69 8d be 08 00 00 00 e8 c5 3a 60 00 44
RSP: 0018:ffffc90003867aa0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8c11c720
RBP: ffffc90003867bc0 R08: 0000000000000000 R09: 0000000000000000
R10: fffffbfff1ad334e R11: 1ffffffff1ad334d R12: ffffffff8c11c720
R13: 1ffff9200070cf60 R14: 0000000000000000 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xc9/0x5c0 net/batman-adv/network-coding.c:723
 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 9634 jiffies! g6849 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:27872 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 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 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729
sched: RT throttling activated