syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4483/1:b..l
	(detected by 0, t=10502 jiffies, g=6417, q=64 ncpus=2)
task:kworker/u4:6    state:R  running task     stack:0     pid:4483  ppid:2      flags:0x00000008
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 preempt_schedule_irq+0x8c/0x1b8 kernel/sched/core.c:6873
 arm64_preempt_schedule_irq+0x44/0x58 arch/arm64/kernel/entry-common.c:265
 __el1_irq arch/arm64/kernel/entry-common.c:474 [inline]
 el1_interrupt+0x3c/0x54 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:755 [inline]
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:825 [inline]
 batadv_iv_ogm_schedule+0x3cc/0xd3c net/batman-adv/bat_iv_ogm.c:868
 batadv_iv_send_outstanding_bat_ogm_packet+0x6f8/0x858 net/batman-adv/bat_iv_ogm.c:1712
 process_one_work+0x7f4/0x13a8 kernel/workqueue.c:2292
 worker_thread+0x8c8/0xfbc kernel/workqueue.c:2439
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864
rcu: rcu_preempt kthread starved for 10505 jiffies! g6417 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:0     pid:16    ppid:2      flags:0x00000008
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 schedule+0xc4/0x170 kernel/sched/core.c:6637
 schedule_timeout+0x180/0x2c8 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2a8/0x134c kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xc0/0x2f8 kernel/rcu/tree.c:1905
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864
rcu: Stack dump where RCU GP kthread last ran:
Task dump for CPU 1:
task:syz.0.27        state:R  running task     stack:0     pid:4510  ppid:4438   flags:0x00000001
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 0xffff0000d5bb9bc0