rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=4a24/1/0x4000000000000000 softirq=57064/57076 fqs=2
rcu: 	(detected by 1, t=10502 jiffies, g=52109, q=581 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 14721 Comm: syz.5.2420 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:mark_usage kernel/locking/lockdep.c:4639 [inline]
RIP: 0010:__lock_acquire+0x658/0x2cf0 kernel/locking/lockdep.c:5191
Code: c0 0f 84 f6 0d 00 00 83 bb 14 0b 00 00 00 74 54 48 8b 7c 24 08 4c 89 ee ba 05 00 00 00 eb 38 85 c9 74 19 31 ed 48 8b 7c 24 08 <4c> 89 ee 31 d2 e8 ee 47 00 00 85 c0 0f 84 c3 0d 00 00 48 8b 44 24
RSP: 0018:ffffc90000007a38 EFLAGS: 00000046
RAX: 00000000000c4000 RBX: ffff88804d43aa20 RCX: 0000000000000001
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff88804d439e80
RBP: 0000000000000000 R08: ffffffff8498f45d R09: ffffffff99b41278
R10: ffff88804cf9f308 R11: ffffed10099f3e63 R12: 0000000000000002
R13: ffff88804d43aa00 R14: ffff88804d439e80 R15: 0000000000000002
FS:  00007f14d9ff66c0(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f37b1937b50 CR3: 0000000078f46000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x6d/0x360 lib/debugobjects.c:873
 debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline]
 debug_deactivate+0x1d/0x1e0 kernel/time/hrtimer.c:483
 __run_hrtimer kernel/time/hrtimer.c:1745 [inline]
 __hrtimer_run_queues+0x2b0/0xc30 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lockdep_unregister_key+0x326/0x3a0 kernel/locking/lockdep.c:6616
Code: 18 0f 84 d1 fd ff ff e8 f8 03 bd 09 89 c7 e8 21 08 00 00 e9 53 fe ff ff e8 17 05 bd 09 41 f7 c7 00 02 00 00 74 b1 fb 40 84 ed <75> b0 eb c1 90 0f 0b 90 e9 15 ff ff ff 90 0f 0b 90 e9 1d ff ff ff
RSP: 0018:ffffc9000ce9f0a0 EFLAGS: 00000246
RAX: 2035cb4b191d3b00 RBX: ffff88802709ba68 RCX: 2035cb4b191d3b00
RDX: ffffffff934263d8 RSI: ffffffff8d7a7180 RDI: ffffffff8bc08360
RBP: ffff88804d439e00 R08: ffffffff81abe7e8 R09: ffffffff8df41a20
R10: dffffc0000000000 R11: fffffbfff1f0440f R12: 0000000000000000
R13: ffff88802709ba69 R14: 0000000000001000 R15: 0000000000000a07
 __qdisc_destroy+0x166/0x400 net/sched/sch_generic.c:1079
 taprio_attach+0x25a/0x380 net/sched/sch_taprio.c:2161
 qdisc_graft+0x1175/0x1590 net/sched/sch_api.c:1162
 __tc_modify_qdisc net/sched/sch_api.c:1761 [inline]
 tc_modify_qdisc+0x16d3/0x2020 net/sched/sch_api.c:1817
 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6967
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 ____sys_sendmsg+0x505/0x820 net/socket.c:2592
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2681
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f14dbd8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f14d9ff6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f14dbfe5fa0 RCX: 00007f14dbd8f749
RDX: 0000000000000000 RSI: 00002000000007c0 RDI: 0000000000000004
RBP: 00007f14dbe13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f14dbfe6038 R14: 00007f14dbfe5fa0 R15: 00007ffe1c82b138
 </TASK>
rcu: rcu_preempt kthread starved for 10498 jiffies! g52109 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:
task:rcu_preempt     state:R  running task     stack:27176 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 2950 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xccf/0x12b0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 4a 9a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 f5 95 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 d9 95
RSP: 0018:ffffc9000bb57620 EFLAGS: 00000293
RAX: ffffffff81b61c77 RBX: 1ffff110170c856d RCX: ffff88802e6a0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000bb577a0 R08: ffffffff8f822077 R09: 1ffffffff1f0440e
R10: dffffc0000000000 R11: fffffbfff1f0440f R12: ffff8880b8642b68
R13: dffffc0000000000 R14: ffff8880b873bb00 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125f35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c30abab CR3: 000000000dd3a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 on_each_cpu include/linux/smp.h:71 [inline]
 smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2711 [inline]
 smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2921
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:874
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>