syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 ticks this GP) idle=cff4/1/0x4000000000000000 softirq=17949/17949 fqs=3
rcu: 	(detected by 1, t=10502 jiffies, g=13581, q=151 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7397 Comm: syz.1.544 Not tainted 6.14.0-rc1-syzkaller-00276-g69b54314c975 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:87 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:123 [inline]
RIP: 0010:lock_is_held_type+0x54/0x150 kernel/locking/lockdep.c:5919
Code: 25 ac 74 85 c0 0f 85 ce 00 00 00 65 4c 8b 25 63 73 ad 74 41 8b 94 24 ec 0a 00 00 85 d2 0f 85 b6 00 00 00 48 89 fd 41 89 f6 9c <8f> 04 24 fa 48 c7 c7 e0 ef 6c 8b 45 31 ff e8 09 17 00 00 4d 8d ac
RSP: 0018:ffffc90000007d38 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff888031bee300
RBP: ffff888031bee300 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffff8880323c8000
R13: 00000000ffffffff R14: 00000000ffffffff R15: ffff888035c18000
FS:  0000555593686500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 000000002824a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_is_held include/linux/lockdep.h:249 [inline]
 advance_sched+0x707/0xc60 net/sched/sch_taprio.c:929
 __run_hrtimer kernel/time/hrtimer.c:1801 [inline]
 __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1865
 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1927
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lockdep_unregister_key+0x1b2/0x2b0 kernel/locking/lockdep.c:6595
Code: 54 fd ff ff 48 89 df e8 9c c3 ff ff 89 c3 e8 05 d9 ff ff 9c 58 f6 c4 02 0f 85 92 00 00 00 41 f7 c5 00 02 00 00 74 01 fb 84 db <75> 4f 5b 5d 41 5c 41 5d 41 5e 41 5f e9 cd 99 0a 00 48 c7 c0 34 69
RSP: 0018:ffffc9000478fa20 EFLAGS: 00000246
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: ffffffff8b6cefe0 RDI: ffffffff8bd34e00
RBP: ffff88804869c298 R08: ffffffff93884190 R09: 000000000002b408
R10: ffffffff96e9f3ef R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000246 R14: ffffffff9704fa28 R15: ffff88804869c2a0
 __qdisc_destroy+0x11a/0x4b0 net/sched/sch_generic.c:1080
 qdisc_put+0xab/0xe0 net/sched/sch_generic.c:1106
 shutdown_scheduler_queue+0xa5/0x160 net/sched/sch_generic.c:1159
 netdev_for_each_tx_queue include/linux/netdevice.h:2590 [inline]
 dev_shutdown+0xad/0x430 net/sched/sch_generic.c:1491
 unregister_netdevice_many_notify+0x9fb/0x1f30 net/core/dev.c:11791
 unregister_netdevice_many net/core/dev.c:11866 [inline]
 unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11736
 unregister_netdevice include/linux/netdevice.h:3329 [inline]
 __tun_detach+0x1241/0x1530 drivers/net/tun.c:685
 tun_detach drivers/net/tun.c:701 [inline]
 tun_chr_close+0xc2/0x230 drivers/net/tun.c:3517
 __fput+0x3ff/0xb70 fs/file_table.c:464
 task_work_run+0x14e/0x250 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0eab38cde9
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:00007fff737cca98 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000001e4db RCX: 00007f0eab38cde9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f0eab5a7ba0 R08: 0000000000000001 R09: 0000000d737ccd8f
R10: 00007f0eab200000 R11: 0000000000000246 R12: 00007f0eab5a5fac
R13: 00007f0eab5a5fa0 R14: ffffffffffffffff R15: 00007fff737ccbb0
 </TASK>
rcu: rcu_preempt kthread starved for 10496 jiffies! g13581 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:27552 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6856
 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2024
 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2226
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 6818 Comm: kworker/u8:27 Not tainted 6.14.0-rc1-syzkaller-00276-g69b54314c975 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0x4c6/0x12c0 kernel/smp.c:885
Code: 0c 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 fc 4c 89 fd 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 fc 04 0c 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 e8 0b 00 00 8b 43 08 31
RSP: 0018:ffffc9001046f928 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8646a00 RCX: ffffffff81adcf0a
RDX: ffff88807bde4880 RSI: ffffffff81adcee4 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000006 R12: ffffed10170c8d41
R13: 0000000000000001 R14: ffff8880b873fe80 R15: ffff8880b8646a08
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fa0dff8 CR3: 000000000df80000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2118 [inline]
 text_poke_bp_batch+0x22b/0x760 arch/x86/kernel/alternative.c:2328
 text_poke_flush arch/x86/kernel/alternative.c:2519 [inline]
 text_poke_flush arch/x86/kernel/alternative.c:2516 [inline]
 text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2526
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x1d7/0x400 kernel/jump_label.c:920
 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate mm/kfence/core.c:850 [inline]
 toggle_allocation_gate+0xfc/0x260 mm/kfence/core.c:842
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>