rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 ticks this GP) idle=267/1/0x4000000000000002 softirq=23264/23264 fqs=0 
	(detected by 1, t=10502 jiffies, g=33021, q=1568)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10158 Comm: syz.4.1130 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:rcu_lockdep_current_cpu_online+0x85/0x130 kernel/rcu/tree.c:1172
Code: 3c 38 00 74 08 48 89 df e8 d8 a2 59 00 48 8b 03 4c 8d b0 c0 b1 03 00 48 8d b8 d8 b1 03 00 48 89 f8 48 c1 e8 03 42 80 3c 38 00 <74> 05 e8 b4 a2 59 00 49 8b 5e 18 49 83 c6 20 4c 89 f0 48 c1 e8 03
RSP: 0018:ffffc90000006e68 EFLAGS: 00000046
RAX: 1ffff110171c763b RBX: ffffffff8be44820 RCX: 05f2a2ae47c64300
RDX: 0000000000000100 RSI: ffffffff8a7a4be0 RDI: ffff8880b8e3b1d8
RBP: ffffc90000006fd0 R08: ffffc90000006f57 R09: ffffc90000006f40
R10: dffffc0000000000 R11: fffff52000000deb R12: 1ffff92000000de4
R13: ffffc90000007020 R14: ffff8880b8e3b1c0 R15: dffffc0000000000
FS:  0000555573de3500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f31fab9e1d4 CR3: 000000002f7e3000 CR4: 00000000003506f0
DR0: 4000000800000000 DR1: 0000200000000700 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
 rcu_read_lock_held+0x1a/0x40 kernel/rcu/update.c:309
 __perf_output_begin kernel/events/ring_buffer.c:170 [inline]
 perf_output_begin_forward+0x1af/0xa30 kernel/events/ring_buffer.c:271
 __perf_event_output kernel/events/core.c:7814 [inline]
 perf_event_output_forward+0x19b/0x2e0 kernel/events/core.c:7832
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525
 perf_swevent_overflow kernel/events/core.c:9601 [inline]
 perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9639
 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031
 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
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 82 fc 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007680 EFLAGS: 00000206
RAX: 05f2a2ae47c64300 RBX: 1ffff92000000ed4 RCX: 05f2a2ae47c64300
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4c00
RBP: ffffc90000007748 R08: ffffffff9101518f R09: 1ffffffff2202a31
R10: dffffc0000000000 R11: fffffbfff2202a32 R12: ffffffff8d123400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 dev_queue_xmit_nit+0x9a9/0xae0 net/core/dev.c:2390
 xmit_one net/core/dev.c:3657 [inline]
 dev_hard_start_xmit+0x140/0x7d0 net/core/dev.c:3678
 __dev_queue_xmit+0x195d/0x2e50 net/core/dev.c:4305
 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+0x65b/0xa50 net/lapb/lapb_timer.c:-1
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:96 [inline]
RIP: 0010:syscall_enter_from_user_mode+0x2a/0x70 kernel/entry/common.c:117
Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 cd f5 ff ff eb 31 eb 35 e8 c4 2e bd f7 e8 bf 2c bd f7 fb 65 48 8b 05 46 4d 40 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 71 21 a5 f7 48
RSP: 0018:ffffc900032aff08 EFLAGS: 00000286
RAX: ffff88802b0f3b80 RBX: 00000000000000e6 RCX: 05f2a2ae47c64300
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4c00
RBP: ffffc900032aff48 R08: ffff8880b8e3b30b R09: 1ffff110171c7661
R10: dffffc0000000000 R11: ffffed10171c7662 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc900032aff58 R15: 0000000000000000
 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f63704daa0e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffeb0905c98 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555573de3500 RCX: 00007f63704daa0e
RDX: 00007ffeb0905cf0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f63707a3da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000004b4fd
R13: 00007f63707a209c R14: 000000000004b37b R15: 00007ffeb0905e20
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g33021 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=23621
rcu: rcu_preempt kthread starved for 10502 jiffies! g33021 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26928 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10158 Comm: syz.4.1130 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:task_wait_context kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4780 [inline]
RIP: 0010:__lock_acquire+0x974/0x7d40 kernel/locking/lockdep.c:5070
Code: 2a 2b 8a 48 c7 c6 20 2d 2b 8a e8 d7 2c 5a 08 49 b8 00 00 00 00 00 fc ff df 0f 0b e9 ee fd ff ff 45 89 e6 65 8b 05 60 79 a5 7e <41> b5 02 85 c0 48 8b 9c 24 a8 00 00 00 75 23 48 8b 84 24 c8 00 00
RSP: 0018:ffffc90000006ae0 EFLAGS: 00000086
RAX: 0000000000000000 RBX: 00000000000e0684 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff910150c0
RBP: ffffc90000006d28 R08: dffffc0000000000 R09: 1ffffffff2202a18
R10: dffffc0000000000 R11: fffffbfff2202a19 R12: 0000000000000000
R13: ffff88802b0f3b80 R14: 0000000000000000 R15: ffffffffffffffff
FS:  0000555573de3500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f31fab9e1d4 CR3: 000000002f7e3000 CR4: 00000000003506f0
DR0: 4000000800000000 DR1: 0000200000000700 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 __perf_output_begin kernel/events/ring_buffer.c:163 [inline]
 perf_output_begin_forward+0xa5/0xa30 kernel/events/ring_buffer.c:271
 __perf_event_output kernel/events/core.c:7814 [inline]
 perf_event_output_forward+0x19b/0x2e0 kernel/events/core.c:7832
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525
 perf_swevent_overflow kernel/events/core.c:9601 [inline]
 perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9639
 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031
 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
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 82 fc 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007680 EFLAGS: 00000206
RAX: 05f2a2ae47c64300 RBX: 1ffff92000000ed4 RCX: 05f2a2ae47c64300
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4c00
RBP: ffffc90000007748 R08: ffffffff9101518f R09: 1ffffffff2202a31
R10: dffffc0000000000 R11: fffffbfff2202a32 R12: ffffffff8d123400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 dev_queue_xmit_nit+0x9a9/0xae0 net/core/dev.c:2390
 xmit_one net/core/dev.c:3657 [inline]
 dev_hard_start_xmit+0x140/0x7d0 net/core/dev.c:3678
 __dev_queue_xmit+0x195d/0x2e50 net/core/dev.c:4305
 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+0x65b/0xa50 net/lapb/lapb_timer.c:-1
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:96 [inline]
RIP: 0010:syscall_enter_from_user_mode+0x2a/0x70 kernel/entry/common.c:117
Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 cd f5 ff ff eb 31 eb 35 e8 c4 2e bd f7 e8 bf 2c bd f7 fb 65 48 8b 05 46 4d 40 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 71 21 a5 f7 48
RSP: 0018:ffffc900032aff08 EFLAGS: 00000286
RAX: ffff88802b0f3b80 RBX: 00000000000000e6 RCX: 05f2a2ae47c64300
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4c00
RBP: ffffc900032aff48 R08: ffff8880b8e3b30b R09: 1ffff110171c7661
R10: dffffc0000000000 R11: ffffed10171c7662 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc900032aff58 R15: 0000000000000000
 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f63704daa0e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffeb0905c98 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555573de3500 RCX: 00007f63704daa0e
RDX: 00007ffeb0905cf0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f63707a3da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000004b4fd
R13: 00007f63707a209c R14: 000000000004b37b R15: 00007ffeb0905e20
 </TASK>