rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4109/1:b..l P3661/1:b..l (detected by 1, t=10502 jiffies, g=8665, q=470) task:udevd state:R running task stack: 0 pid: 3661 ppid: 1 flags:0x00000004 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_common+0x138/0x218 kernel/sched/core.c:6552 preempt_schedule+0x64/0x84 kernel/sched/core.c:6577 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x108/0x14c kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:418 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x11c/0x178 kernel/sched/wait.c:205 sock_def_readable+0x150/0x278 net/core/sock.c:3093 __netlink_sendskb net/netlink/af_netlink.c:1264 [inline] netlink_sendskb+0xa4/0x178 net/netlink/af_netlink.c:1270 netlink_unicast+0x2d8/0x8b0 net/netlink/af_netlink.c:1359 netlink_sendmsg+0x6e8/0x9cc net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x61c/0x920 net/socket.c:2436 ___sys_sendmsg+0x1d0/0x240 net/socket.c:2490 __sys_sendmsg net/socket.c:2519 [inline] __do_sys_sendmsg net/socket.c:2528 [inline] __se_sys_sendmsg net/socket.c:2526 [inline] __arm64_sys_sendmsg+0x1a8/0x254 net/socket.c:2526 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 task:kworker/1:4 state:R running task stack: 0 pid: 4109 ppid: 2 flags:0x00000008 Workqueue: events nsim_fib_event_work 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+0x8/0x10 arch/arm64/include/asm/irqflags.h:122 lock_is_held include/linux/lockdep.h:287 [inline] rcu_read_lock_held+0x34/0x50 kernel/rcu/update.c:311 fib_find_node+0x98/0x2a8 net/ipv4/fib_trie.c:942 fib_find_matching_alias net/ipv4/fib_trie.c:1024 [inline] fib_alias_hw_flags_set+0x148/0x8c0 net/ipv4/fib_trie.c:1047 nsim_fib4_rt_hw_flags_set drivers/net/netdevsim/fib.c:351 [inline] nsim_fib4_rt_add drivers/net/netdevsim/fib.c:368 [inline] nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:430 [inline] nsim_fib4_event drivers/net/netdevsim/fib.c:462 [inline] nsim_fib_event drivers/net/netdevsim/fib.c:882 [inline] nsim_fib_event_work+0x12dc/0x2704 drivers/net/netdevsim/fib.c:1483 process_one_work+0x79c/0x1140 kernel/workqueue.c:2310 process_scheduled_works kernel/workqueue.c:2373 [inline] worker_thread+0xb64/0x101c kernel/workqueue.c:2459 kthread+0x374/0x454 kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:855 rcu: rcu_preempt kthread starved for 10500 jiffies! g8665 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:855 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 1: task:syz.2.24 state:R running task stack: 0 pid: 5544 ppid: 4813 flags:0x00000000 Call trace: dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 sched_show_task+0x3c8/0x4b4 kernel/sched/core.c:8640 dump_cpu_task+0x84/0xa8 kernel/sched/core.c:10927 rcu_check_gp_kthread_starvation+0x1e8/0x274 kernel/rcu/tree_stall.h:488 print_other_cpu_stall+0x1a24/0x1c10 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x1558/0x1810 kernel/rcu/tree.c:2619 update_process_times+0x1c4/0x260 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x30c/0x4bc kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1690 [inline] __hrtimer_run_queues+0x3fc/0xb6c kernel/time/hrtimer.c:1754 hrtimer_interrupt+0x2bc/0xb5c kernel/time/hrtimer.c:1816 timer_handler drivers/clocksource/arm_arch_timer.c:659 [inline] arch_timer_handler_virt+0x74/0x88 drivers/clocksource/arm_arch_timer.c:670 handle_percpu_devid_irq+0x29c/0x76c kernel/irq/chip.c:930 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq_desc kernel/irq/irqdesc.c:652 [inline] handle_domain_irq+0x144/0x1fc kernel/irq/irqdesc.c:707 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765 call_on_irq_stack+0x24/0x30 arch/arm64/kernel/entry.S:855 do_interrupt_handler+0x6c/0x88 arch/arm64/kernel/entry-common.c:267 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454 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_enable arch/arm64/include/asm/irqflags.h:35 [inline] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0xa0/0x128 kernel/locking/spinlock.c:202 spin_unlock_irq include/linux/spinlock.h:413 [inline] get_signal+0xfac/0x1340 kernel/signal.c:2903 do_signal arch/arm64/kernel/signal.c:893 [inline] do_notify_resume+0x29c/0x3128 arch/arm64/kernel/signal.c:946 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline] el0_svc+0xf0/0x1e0 arch/arm64/kernel/entry-common.c:609 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584