rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5121/1:b..l (detected by 0, t=10502 jiffies, g=12121, q=129) task:kworker/u4:7 state:R running task stack: 0 pid: 5121 ppid: 2 flags:0x00000008 Workqueue: bat_events batadv_nc_worker Call trace: __switch_to+0x2f4/0x558 arch/arm64/kernel/process.c:521 context_switch kernel/sched/core.c:5030 [inline] __schedule+0xe00/0x1c0c kernel/sched/core.c:6376 preempt_schedule_irq+0x90/0x214 kernel/sched/core.c:6780 arm64_preempt_schedule_irq+0x14c/0x21c arch/arm64/kernel/entry-common.c:260 el1_interrupt+0x40/0x58 arch/arm64/kernel/entry-common.c:463 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline] lock_acquire+0x234/0x620 kernel/locking/lockdep.c:5626 rcu_lock_acquire+0x40/0x4c 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+0xc0/0x554 net/batman-adv/network-coding.c:723 process_one_work+0x79c/0x1140 kernel/workqueue.c:2310 worker_thread+0x8f4/0x101c kernel/workqueue.c:2457 kthread+0x374/0x454 kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 rcu: rcu_preempt kthread starved for 10502 jiffies! g12121 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: 15 ppid: 2 flags:0x00000008 Call trace: __switch_to+0x2f4/0x558 arch/arm64/kernel/process.c:521 context_switch kernel/sched/core.c:5030 [inline] __schedule+0xe00/0x1c0c kernel/sched/core.c:6376 schedule+0x11c/0x1c8 kernel/sched/core.c:6459 schedule_timeout+0x180/0x2c8 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x25c/0x11f0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xc4/0x2a8 kernel/rcu/tree.c:2145 kthread+0x374/0x454 kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 1: task:syz.2.18 state:R running task stack: 0 pid: 5234 ppid: 4777 flags:0x00000001 Call trace: __switch_to+0x2f4/0x558 arch/arm64/kernel/process.c:521 0xffff0000cc4b2518