rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=6f6/1/0x4000000000000000 softirq=10195/10196 fqs=1 (t=27930 jiffies g=9233 q=413) rcu: rcu_preempt kthread starved for 27901 jiffies! g9233 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: rcu_preempt R running task 29112 10 2 0x00004000 Call Trace: context_switch kernel/sched/core.c:3458 [inline] __schedule+0x8ea/0x2210 kernel/sched/core.c:4219 schedule+0xd0/0x2a0 kernel/sched/core.c:4294 schedule_timeout+0x148/0x250 kernel/time/timer.c:1908 rcu_gp_fqs_loop kernel/rcu/tree.c:1874 [inline] rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2044 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 NMI backtrace for cpu 1 CPU: 1 PID: 6799 Comm: syz-executor494 Not tainted 5.8.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:320 print_cpu_stall kernel/rcu/tree_stall.h:553 [inline] check_cpu_stall kernel/rcu/tree_stall.h:627 [inline] rcu_pending kernel/rcu/tree.c:3489 [inline] rcu_sched_clock_irq.cold+0x5b3/0xccc kernel/rcu/tree.c:2504 update_process_times+0x25/0x60 kernel/time/timer.c:1737 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x108/0x290 kernel/time/tick-sched.c:1320 __run_hrtimer kernel/time/hrtimer.c:1520 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1584 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1646 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] sysvec_apic_timer_interrupt+0xe0/0x120 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:585 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x8c/0xe0 kernel/locking/spinlock.c:191 Code: 48 c7 c0 88 e0 b4 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 37 48 83 3d e3 52 cc 01 00 74 22 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 35 e5 66 f9 65 8b 05 fe 70 19 78 RSP: 0018:ffffc900016672c0 EFLAGS: 00000282 RAX: 1ffffffff1369c11 RBX: 0000000000000282 RCX: 0000000000000002 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000282 RBP: ffff888093a052e8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000282 R13: 00000078100c35c3 R14: ffff888093a05000 R15: 0000000000000000 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] taprio_change+0x1fdc/0x2960 net/sched/sch_taprio.c:1557 taprio_init+0x52e/0x670 net/sched/sch_taprio.c:1670 qdisc_create+0x4b6/0x12e0 net/sched/sch_api.c:1246 tc_modify_qdisc+0x4c8/0x1990 net/sched/sch_api.c:1662 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5461 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x443819 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 0f fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff687c83d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000443819 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000004 RBP: 00007fff687c83e0 R08: 0000000001bbbbbb R09: 0000000001bbbbbb R10: 0000000001bbbbbb R11: 0000000000000246 R12: 00007fff687c83f0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000