rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=506/1/0x4000000000000000 softirq=180146/180147 fqs=0 (t=10502 jiffies g=349225 q=66) rcu: rcu_preempt kthread timer wakeup didn't happen for 10502 jiffies! g349225 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=120754 rcu: rcu_preempt kthread starved for 10506 jiffies! g349225 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:28864 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4683 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5940 schedule+0xd3/0x270 kernel/sched/core.c:6019 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1878 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline] rcu_gp_kthread+0xd34/0x1980 kernel/rcu/tree.c:2169 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 412 Comm: kworker/u4:5 Not tainted 5.14.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: tipc_rcv tipc_conn_recv_work RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:90 [inline] RIP: 0010:kvm_wait arch/x86/kernel/kvm.c:888 [inline] RIP: 0010:kvm_wait+0xaf/0xf0 arch/x86/kernel/kvm.c:871 Code: 10 c3 c3 89 74 24 0c 48 89 3c 24 e8 6b a1 48 00 8b 74 24 0c 48 8b 3c 24 eb 82 e8 7c a6 48 00 eb 07 0f 00 2d 93 e3 55 08 fb f4 9b eb 07 0f 00 2d 86 e3 55 08 f4 eb c5 89 74 24 0c 48 89 3c 24 RSP: 0000:ffffc900012ffb10 EFLAGS: 00000202 RAX: 00000000047f5726 RBX: 0000000000000000 RCX: 1ffffffff1fa79b2 RDX: 0000000000000000 RSI: 0000000000000201 RDI: 0000000000000000 RBP: ffff8880992ed858 R08: 0000000000000001 R09: ffffffff8fcd29bf R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: ffffed101325db0b R14: 0000000000000001 R15: ffff8880b9d52880 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002000c418 CR3: 00000000a26ee000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x8b8/0xb40 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x200/0x2b0 kernel/locking/spinlock_debug.c:113 spin_lock_bh include/linux/spinlock.h:359 [inline] tipc_conn_kref_release+0x47/0x380 net/tipc/topsrv.c:129 kref_put include/linux/kref.h:65 [inline] conn_put net/tipc/topsrv.c:147 [inline] tipc_conn_recv_work+0x14a/0x190 net/tipc/topsrv.c:430 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 NMI backtrace for cpu 0 CPU: 0 PID: 155 Comm: kworker/u4:3 Not tainted 5.14.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:342 print_cpu_stall kernel/rcu/tree_stall.h:625 [inline] check_cpu_stall kernel/rcu/tree_stall.h:700 [inline] rcu_pending kernel/rcu/tree.c:3922 [inline] rcu_sched_clock_irq.cold+0x9f/0x747 kernel/rcu/tree.c:2641 update_process_times+0x16d/0x200 kernel/time/timer.c:1782 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:tipc_topsrv_stop net/tipc/topsrv.c:691 [inline] RIP: 0010:tipc_topsrv_exit_net+0x1fa/0x5d0 net/tipc/topsrv.c:715 Code: e8 2b 15 d2 f8 85 db 0f 84 2b 03 00 00 e8 de 0d d2 f8 4c 8b 6c 24 08 31 db 48 b8 00 00 00 00 00 fc ff df 49 c1 ed 03 49 01 c5 c1 0d d2 f8 48 63 f3 48 89 ef e8 d6 b6 4c fb 48 85 c0 49 89 c7 RSP: 0018:ffffc9000154fbf0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 000000007a5e12f1 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffff888013bd8000 RDI: 0000000000000003 RBP: ffff8880992ed800 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff88a37bd9 R11: 0000000000000000 R12: ffff8880992ed858 R13: ffffed101325db13 R14: ffff88803a30df80 R15: 0000000000000001 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:175 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:595 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295