rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10139 ticks this GP) idle=163/1/0x4000000000000002 softirq=25061/25061 fqs=2 (t=10500 jiffies g=29705 q=68) rcu: rcu_preempt kthread starved for 10401 jiffies! g29705 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: 0 pid: 15 ppid: 2 flags:0x00000008 Call trace: __switch_to+0x308/0x5e8 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 prepare_to_swait_event+0x2a0/0x2ec kernel/sched/swait.c:120 rcu_gp_fqs_loop+0x238/0x13d4 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 1: task:syz.2.1454 state:R running task stack: 0 pid: 9236 ppid: 7172 flags:0x00000001 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 sched_show_task+0x43c/0x574 kernel/sched/core.c:8637 dump_cpu_task+0x84/0xa8 kernel/sched/core.c:10924 rcu_check_gp_kthread_starvation+0x1f0/0x254 kernel/rcu/tree_stall.h:488 print_cpu_stall+0x554/0xc7c kernel/rcu/tree_stall.h:631 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xd20/0x1b8c kernel/rcu/tree.c:2619 update_process_times+0x1d4/0x270 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x340/0x4f8 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x458/0xca4 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x2c0/0xb64 kernel/time/hrtimer.c:1814 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/0x7fc 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+0xec/0x178 kernel/irq/irqdesc.c:707 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899 do_interrupt_handler+0x74/0x94 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_restore+0x8/0x10 arch/arm64/include/asm/irqflags.h:122 lock_is_held include/linux/lockdep.h:287 [inline] ___might_sleep+0x48/0x4dc kernel/sched/core.c:9602 __might_sleep+0x98/0xf0 kernel/sched/core.c:9590 __might_fault+0x80/0x128 mm/memory.c:5352 __copy_from_user include/linux/uaccess.h:109 [inline] restore_fpsimd_context arch/arm64/kernel/signal.c:204 [inline] restore_sigframe arch/arm64/kernel/signal.c:528 [inline] __arm64_sys_rt_sigreturn+0x16b8/0x22ec arch/arm64/kernel/signal.c:555 __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+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Task dump for CPU 1: task:syz.2.1454 state:R running task stack: 0 pid: 9236 ppid: 7172 flags:0x00000001 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 sched_show_task+0x43c/0x574 kernel/sched/core.c:8637 dump_cpu_task+0x84/0xa8 kernel/sched/core.c:10924 rcu_dump_cpu_stacks+0x2d8/0x540 kernel/rcu/tree_stall.h:350 print_cpu_stall+0x558/0xc7c kernel/rcu/tree_stall.h:633 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xd20/0x1b8c kernel/rcu/tree.c:2619 update_process_times+0x1d4/0x270 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x340/0x4f8 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x458/0xca4 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x2c0/0xb64 kernel/time/hrtimer.c:1814 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/0x7fc 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+0xec/0x178 kernel/irq/irqdesc.c:707 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899 do_interrupt_handler+0x74/0x94 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_restore+0x8/0x10 arch/arm64/include/asm/irqflags.h:122 lock_is_held include/linux/lockdep.h:287 [inline] ___might_sleep+0x48/0x4dc kernel/sched/core.c:9602 __might_sleep+0x98/0xf0 kernel/sched/core.c:9590 __might_fault+0x80/0x128 mm/memory.c:5352 __copy_from_user include/linux/uaccess.h:109 [inline] restore_fpsimd_context arch/arm64/kernel/signal.c:204 [inline] restore_sigframe arch/arm64/kernel/signal.c:528 [inline] __arm64_sys_rt_sigreturn+0x16b8/0x22ec arch/arm64/kernel/signal.c:555 __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+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584