rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=a444/1/0x4000000000000000 softirq=105345/105356 fqs=15
rcu: (detected by 1, t=10505 jiffies, g=102189, q=613 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 19480 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:104 [inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x53/0x80 kernel/locking/spinlock.c:194
Code: 74 05 e8 60 97 6c f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 e8 44 85 34 f6 65 8b 05 4d e8 23 07 <85> c0 74 18 5b 41 5e e9 1c 19 b4 f5 cc e8 0b 69 fd ff f7 c3 00 02
RSP: 0018:ffffc90000007c90 EFLAGS: 00000093
RAX: 0000000080010001 RBX: 0000000000000086 RCX: 0000000000010000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: ffff8880529ee428 R08: ffffffff99adc4bb R09: 1ffffffff335b897
R10: dffffc0000000000 R11: fffffbfff335b898 R12: ffff8880529ee438
R13: 0000000000000002 R14: ffffffff99adc4b8 R15: 1ffff1100a53dc87
FS: 00005555656ee500(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f78805e1e6c CR3: 0000000038a93000 CR4: 0000000000350ef0
Call Trace:
debug_object_activate+0x318/0x540 lib/debugobjects.c:836
debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline]
debug_activate kernel/time/hrtimer.c:477 [inline]
enqueue_hrtimer+0x30/0x380 kernel/time/hrtimer.c:1081
__run_hrtimer kernel/time/hrtimer.c:1794 [inline]
__hrtimer_run_queues+0x636/0xc30 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
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_is_held_type+0x107/0x150 kernel/locking/lockdep.c:5945
Code: 18 00 00 b8 ff ff ff ff 65 0f c1 05 93 c1 26 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 c5 ac b6 f5 cc 90 0f 0b 90 48 c7
RSP: 0018:ffffc9000c3af438 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000046
RDX: ffff88807baabd00 RSI: ffffffff8d975f94 RDI: ffffffff8bc083e0
RBP: 00000000ffffffff R08: ffffffff8263495c R09: ffffffff8df41aa0
R10: dffffc0000000000 R11: ffffed102808c037 R12: 0000000000000246
R13: ffff88807baabd00 R14: ffffffff8df41aa0 R15: 0000000000000008
kernfs_root+0xf6/0x230 fs/kernfs/kernfs-internal.h:76
__kernfs_remove+0x40f/0x650 fs/kernfs/dir.c:1524
kernfs_remove_by_name_ns+0xaf/0x130 fs/kernfs/dir.c:1722
kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
remove_files fs/sysfs/group.c:28 [inline]
sysfs_remove_group+0xfc/0x2f0 fs/sysfs/group.c:328
netdev_queue_update_kobjects+0x599/0x6c0 net/core/net-sysfs.c:2070
remove_queue_kobjects net/core/net-sysfs.c:2170 [inline]
netdev_unregister_kobject+0x11f/0x450 net/core/net-sysfs.c:2325
unregister_netdevice_many_notify+0x1ddd/0x2340 net/core/dev.c:12418
unregister_netdevice_many net/core/dev.c:12446 [inline]
unregister_netdevice_queue+0x317/0x350 net/core/dev.c:12260
unregister_netdevice include/linux/netdevice.h:3405 [inline]
nsim_destroy+0x1e5/0x680 drivers/net/netdevsim/netdev.c:1180
__nsim_dev_port_del+0x14d/0x1b0 drivers/net/netdevsim/dev.c:1528
nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1540 [inline]
nsim_dev_reload_destroy+0x288/0x490 drivers/net/netdevsim/dev.c:1763
nsim_drv_remove+0x58/0x160 drivers/net/netdevsim/dev.c:1778
device_remove drivers/base/dd.c:569 [inline]
__device_release_driver drivers/base/dd.c:1282 [inline]
device_release_driver_internal+0x46f/0x800 drivers/base/dd.c:1305
bus_remove_device+0x34d/0x440 drivers/base/bus.c:616
device_del+0x511/0x8e0 drivers/base/core.c:3878
device_unregister+0x21/0x100 drivers/base/core.c:3919
nsim_bus_dev_del drivers/net/netdevsim/bus.c:483 [inline]
del_device_store+0x2aa/0x360 drivers/net/netdevsim/bus.c:244
kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f528cb8e1ff
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007ffcb14befa0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f528cb8e1ff
RDX: 0000000000000001 RSI: 00007ffcb14beff0 RDI: 0000000000000005
RBP: 00007f528cc152cb R08: 0000000000000000 R09: 00007ffcb14bedf7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffcb14beff0 R14: 00007f528d914620 R15: 0000000000000003
rcu: rcu_preempt kthread starved for 10430 jiffies! g102189 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:27472 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 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+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 6042 Comm: kworker/1:9 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events fqdir_free_fn
RIP: 0010:native_pause arch/x86/include/asm/vdso/processor.h:13 [inline]
RIP: 0010:cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline]
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_single+0x388/0x570 kernel/smp.c:687
Code: 44 8b 33 44 89 f6 83 e6 01 31 ff e8 72 ad 0b 00 41 83 e6 01 75 11 e8 27 a9 0b 00 4d 89 fe eb 3f e8 1d a9 0b 00 eb 3c 4d 89 fe 90 43 0f b6 04 2c 84 c0 75 0f f7 03 01 00 00 00 74 1d e8 00 a9
RSP: 0018:ffffc900052878e0 EFLAGS: 00000293
RAX: ffffffff81b54ec0 RBX: ffffc90005287928 RCX: ffff888027391e80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900052879b8 R08: ffffffff8f822277 R09: 1ffffffff1f0444e
R10: dffffc0000000000 R11: ffffffff81717100 R12: 1ffff92000a50f25
R13: dffffc0000000000 R14: 1ffff92000a50f20 R15: 1ffff92000a50f20
FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6ac0372100 CR3: 000000007c0e4000 CR4: 0000000000350ef0
Call Trace:
rcu_barrier+0x360/0x570 kernel/rcu/tree.c:3868
fqdir_free_fn+0x33/0x140 net/ipv4/inet_fragment.c:166
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+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246