rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5684/1:b..l P3627/1:b..l
	(detected by 0, t=10502 jiffies, g=20065, q=36)
task:kworker/u4:5    state:R  running task     stack:20992 pid: 3627 ppid:     2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6777
 irqentry_exit+0x53/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627
Code: 2b 00 74 08 4c 89 f7 e8 4c 7b 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90003167a80 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff9200062cf5c RCX: 1ffff9200062cefc
RDX: dffffc0000000000 RSI: ffffffff8a8b3cc0 RDI: ffffffff8ad8f7c0
RBP: ffffc90003167bd8 R08: dffffc0000000000 R09: fffffbfff20e1e19
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200062cf58
R13: dffffc0000000000 R14: ffffc90003167ae0 R15: 0000000000000246
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xc1/0x5b0 net/batman-adv/network-coding.c:723
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
task:syz.4.387       state:R  running task     stack:27256 pid: 5684 ppid:  3575 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6777
 irqentry_exit+0x53/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:count_memcg_event_mm+0x10e/0x3e0 include/linux/memcontrol.h:1079
Code: b8 4f c7 ff c6 05 ab 8e 1c 0c 01 48 c7 c7 00 6f 94 8a be e5 02 00 00 48 c7 c2 40 6f 94 8a e8 79 f7 a9 ff 49 81 c7 d0 05 00 00 <4c> 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 4c 18 11 00
RSP: 0000:ffffc9000342fb40 EFLAGS: 00000282
RAX: ffffffff81b911af RBX: 0000000000000001 RCX: 0000000000040000
RDX: ffffc90003eca000 RSI: 000000000002cecc RDI: 000000000002cecd
RBP: ffffc9000342fc10 R08: ffffffff81b9119d R09: fffffbfff20e1e19
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000014
R13: dffffc0000000000 R14: 1ffff92000685f6c R15: ffff888029efafd0
 handle_mm_fault+0x161/0x5950 mm/memory.c:4834
 do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
RIP: 0033:0x7f796cd3bc96
RSP: 002b:00007f796b2f34a0 EFLAGS: 00010206
RAX: 0000000000472001 RBX: 00007f796b2f3540 RCX: 00000000000000ac
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007f796b2f35e0
RBP: 0000000000000102 R08: 00007f7962ed4000 R09: 0000000000472000
R10: 0000000000000000 R11: 00007f796b2f3550 R12: 0000000000000001
R13: 00007f796cef9880 R14: 0000000000000000 R15: 00007f796b2f35e0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10551 jiffies! g20065 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=7866
rcu: rcu_preempt kthread starved for 10557 jiffies! g20065 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
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:I stack:26488 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 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: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 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562