rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=15a/1/0x4000000000000000 softirq=92519/92522 fqs=8 (detected by 1, t=10502 jiffies, g=175405, q=136) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 21114 Comm: syz-executor.1 Not tainted 5.8.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_wait_context kernel/locking/lockdep.c:4070 [inline] RIP: 0010:__lock_acquire+0x5c5/0x56e0 kernel/locking/lockdep.c:4330 Code: eb 12 41 83 ef 01 49 83 ed 28 41 83 ff ff 0f 84 83 0b 00 00 49 8d 4d df 4c 89 e8 4c 89 ef 48 c1 e8 03 83 e7 07 42 0f b6 04 30 <40> 38 f8 7f 08 84 c0 0f 85 13 32 00 00 0f b6 41 21 31 f0 a8 60 74 RSP: 0018:ffffc90000007a68 EFLAGS: 00000002 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff888044c769f8 RDX: 0000000000000003 RSI: 0000000000000040 RDI: 0000000000000001 RBP: ffff888044c76a48 R08: 0000000000000000 R09: ffffffff8c58fa27 R10: fffffbfff18b1f44 R11: 0000000000000001 R12: ffff888044c76100 R13: ffff888044c76a19 R14: dffffc0000000000 R15: 0000000000000001 FS: 00007f72df266700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31229000 CR3: 00000000623b7000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:4959 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:159 debug_object_activate+0x12e/0x3e0 lib/debugobjects.c:636 debug_hrtimer_activate kernel/time/hrtimer.c:416 [inline] debug_activate kernel/time/hrtimer.c:476 [inline] enqueue_hrtimer+0x27/0x3f0 kernel/time/hrtimer.c:965 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0xc1e/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:596 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [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 40 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 fb a6 cd 01 00 74 22 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 35 39 68 f9 65 8b 05 5e c5 1a 78 RSP: 0018:ffffc90016df72c0 EFLAGS: 00000282 RAX: 1ffffffff1369c08 RBX: 0000000000000282 RCX: 0000000000000002 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000282 RBP: ffff88809586c2e8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000282 R13: 161fc0053b5e94df R14: ffff88809586c000 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:5460 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:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f72df265c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000005027a0 RCX: 000000000045cb29 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000006 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000a44 R14: 00000000004cd2b2 R15: 00007f72df2666d4 rcu: rcu_preempt kthread starved for 10485 jiffies! g175405 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: rcu_preempt R running task 29056 10 2 0x00004000 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_timeout+0x148/0x250 kernel/time/timer.c:1897 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