rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2664 jiffies s: 2549 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:ct_dynticks include/linux/context_tracking_state.h:61 [inline]
RIP: 0010:ct_nmi_enter+0xd5/0x170 kernel/context_tracking.c:299
Code: 66 90 48 c7 c7 c0 dd 94 8a e8 f7 08 00 00 65 48 8b 05 27 86 d5 75 48 c7 c7 c0 dd 94 8a e8 e3 08 00 00 65 48 8b 05 13 86 d5 75 <e8> b6 07 00 00 89 c3 83 f8 08 73 6f 48 8b 1c dd 80 19 65 8c 48 8d
RSP: 0018:ffffc900001e03f0 EFLAGS: 00000082
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 5c2b8e58b7be3100
RDX: 0000000000000000 RSI: ffffffff8a94ddc0 RDI: ffffffff8adf0d20
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8880b8f35800 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555694f9328 CR3: 0000000077796000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 irqentry_enter+0x3c/0x50 kernel/entry/common.c:362
 sysvec_irq_work+0xa/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 d2 33 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900001e04e0 EFLAGS: 00000206
RAX: 5c2b8e58b7be3100 RBX: 1ffff9200003c0a4 RCX: 5c2b8e58b7be3100
RDX: dffffc0000000000 RSI: ffffffff8a8c10a0 RDI: ffffffff8adf0d20
RBP: ffffc900001e05d0 R08: ffffffff90af7307 R09: 1ffffffff215ee60
R10: dffffc0000000000 R11: fffffbfff215ee61 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 dev_queue_xmit_nit+0xa80/0xbb0 net/core/dev.c:2370
 xmit_one net/core/dev.c:3679 [inline]
 dev_hard_start_xmit+0x154/0x870 net/core/dev.c:3699
 sch_direct_xmit+0x25a/0x4b0 net/sched/sch_generic.c:345
 __dev_xmit_skb net/core/dev.c:3920 [inline]
 __dev_queue_xmit+0x1771/0x37c0 net/core/dev.c:4325
 lapb_data_transmit+0x86/0xa0 net/lapb/lapb_iface.c:447
 lapb_transmit_buffer+0x15f/0x1f0 net/lapb/lapb_out.c:149
 lapb_t1timer_expiry+0x652/0xa70 net/lapb/lapb_timer.c:-1
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742
Code: 48 89 df e8 47 c2 9b f7 e9 44 ff ff ff e8 3d 07 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d 57 eb 4e 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffc90000177de8 EFLAGS: 000002c6
RAX: 5c2b8e58b7be3100 RBX: ffffffff8a37c257 RCX: 5c2b8e58b7be3100
RDX: 0000000000000001 RSI: ffffffff8a8c10a0 RDI: ffffffff8adf0d20
RBP: ffffc90000177f20 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff88813fef9dc0 R15: 1ffff9200002efc8
 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x3a2/0x680 kernel/sched/idle.c:323
 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:422
 start_secondary+0xe4/0xf0 arch/x86/kernel/smpboot.c:281
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.844 msecs