rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4190/1:b..l (detected by 1, t=10502 jiffies, g=26841, q=123) task:kworker/u4:13 state:R running task stack: 0 pid: 4190 ppid: 2 flags:0x00000008 Workqueue: netns cleanup_net Call trace: __switch_to+0x308/0x588 arch/arm64/kernel/process.c:518 context_switch kernel/sched/core.c:5027 [inline] __schedule+0xf10/0x1e48 kernel/sched/core.c:6373 preempt_schedule_irq+0x90/0x274 kernel/sched/core.c:6777 arm64_preempt_schedule_irq+0x174/0x2c4 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 __sanitizer_cov_trace_pc+0x8/0xac kernel/kcov.c:199 dccp_v4_exit_batch+0x20/0x2c net/dccp/ipv4.c:1040 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x5e0/0x9bc net/core/net_namespace.c:599 process_one_work+0x790/0x11b8 kernel/workqueue.c:2310 worker_thread+0x910/0x1034 kernel/workqueue.c:2457 kthread+0x37c/0x45c kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 rcu: rcu_preempt kthread starved for 10504 jiffies! g26841 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: 0 pid: 15 ppid: 2 flags:0x00000008 Call trace: __switch_to+0x308/0x588 arch/arm64/kernel/process.c:518 context_switch kernel/sched/core.c:5027 [inline] __schedule+0xf10/0x1e48 kernel/sched/core.c:6373 preempt_schedule_common+0x140/0x260 kernel/sched/core.c:6549 preempt_schedule+0x64/0x84 kernel/sched/core.c:6574 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x114/0x158 kernel/locking/spinlock.c:194 finish_swait+0x170/0x1ac kernel/sched/swait.c:142 rcu_gp_fqs_loop+0x28c/0x13d4 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xc4/0x2c4 kernel/rcu/tree.c:2145 kthread+0x37c/0x45c 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 0: task:syz.6.1802 state:R running task stack: 0 pid: 9849 ppid: 4520 flags:0x00000001 Call trace: __switch_to+0x308/0x588 arch/arm64/kernel/process.c:518 0xffff800021e07860