rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10517 ticks this GP) idle=7e0c/1/0x4000000000000000 softirq=163754/163756 fqs=13 (t=10500 jiffies g=207837 q=39 ncpus=2) rcu: rcu_preempt kthread starved for 10473 jiffies! g207837 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:28704 pid: 16 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5182 [inline] __schedule+0xadf/0x52b0 kernel/sched/core.c:6494 schedule+0xda/0x1b0 kernel/sched/core.c:6570 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1935 rcu_gp_fqs_loop+0x190/0x910 kernel/rcu/tree.c:1657 rcu_gp_kthread+0x236/0x360 kernel/rcu/tree.c:1854 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x6f/0xb0 drivers/acpi/processor_idle.c:112 NMI backtrace for cpu 1 CPU: 1 PID: 1237 Comm: aoe_tx0 Not tainted 6.0.0-rc6-syzkaller-00281-g1707c39ae309 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x46/0x14f lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x206/0x250 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_dump_cpu_stacks+0x2c7/0x4d0 kernel/rcu/tree_stall.h:371 print_cpu_stall kernel/rcu/tree_stall.h:660 [inline] check_cpu_stall kernel/rcu/tree_stall.h:744 [inline] rcu_pending kernel/rcu/tree.c:3660 [inline] rcu_sched_clock_irq.cold+0x9f/0x79c kernel/rcu/tree.c:2342 update_process_times+0x11a/0x1a0 kernel/time/timer.c:1839 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:243 tick_sched_timer+0xee/0x120 kernel/time/tick-sched.c:1480 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:194 Code: 74 24 10 e8 da 76 db f7 48 89 ef e8 62 f8 db f7 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 a3 b9 ce f7 65 8b 05 fc 45 7f 76 85 c0 74 0a 5b 5d c3 e8 00 86 RSP: 0018:ffffc9000504fa90 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000200 RCX: 1ffffffff212eb7e RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000001 RBP: ffffffff91488af8 R08: 0000000000000001 R09: ffffffff908e1acf R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000020 R13: ffff8880175e78b0 R14: ffff88801dd60fe0 R15: 0000000000000001 spin_unlock_irqrestore include/linux/spinlock.h:404 [inline] uart_write+0x423/0x570 drivers/tty/serial/serial_core.c:589 handle_tx+0x204/0x610 drivers/net/caif/caif_serial.c:236 __netdev_start_xmit include/linux/netdevice.h:4819 [inline] netdev_start_xmit include/linux/netdevice.h:4833 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x183/0x880 net/core/dev.c:3606 __dev_queue_xmit+0x2c31/0x3ad0 net/core/dev.c:4256 dev_queue_xmit include/linux/netdevice.h:3008 [inline] tx+0x6a/0xc0 drivers/block/aoe/aoenet.c:63 kthread+0x1e7/0x3b0 drivers/block/aoe/aoecmd.c:1229 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306