rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (0 ticks this GP) idle=df44/1/0x4000000000000002 softirq=65087/65087 fqs=2
rcu: (detected by 1, t=10502 jiffies, g=74401, q=69 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3801 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3821 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3876 [inline]
RIP: 0010:__lock_acquire+0xb17/0x2cf0 kernel/locking/lockdep.c:5237
Code: 67 92 0e 48 c7 c6 be 88 0c 8e 67 48 0f b9 3a 90 48 bb eb 83 b5 80 46 86 c8 61 48 0f af dd 48 c1 eb 2d 48 8b 04 dd a0 43 fd 93 <48> 85 c0 0f 94 c1 48 83 c0 f8 0f 94 c2 08 ca 0f 84 1c 01 00 00 e8
RSP: 0018:ffffc90000007b40 EFLAGS: 00000017
RAX: ffffffff9441f298 RBX: 0000000000071a55 RCX: 0000000000040000
RDX: 0000000016fc235a RSI: 000000004c4a1974 RDI: ffffffff8e692ec0
RBP: ff21dce2769801df R08: ffffffff84bcd723 R09: ffffffff9a641810
R10: dffffc0000000000 R11: fffff52000000fac R12: ffffffff8e693aa0
R13: ffffffff8e693aa0 R14: ffffffff8e692ec0 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff888125289000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0fb5d89ff8 CR3: 000000006bd11000 CR4: 0000000000350ef0
Call Trace:
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
debug_object_activate+0x83/0x580 lib/debugobjects.c:835
debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline]
debug_activate kernel/time/hrtimer.c:528 [inline]
enqueue_hrtimer+0xa9/0x2c0 kernel/time/hrtimer.c:1109
__run_hrtimer kernel/time/hrtimer.c:1946 [inline]
__hrtimer_run_queues+0x4d2/0xa20 kernel/time/hrtimer.c:1994
hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:steal_cookie_task kernel/sched/core.c:6402 [inline]
RIP: 0010:sched_core_balance+0x59e/0xde0 kernel/sched/core.c:6423
Code: c7 48 e8 95 c7 15 0a e9 75 05 00 00 48 8b 5c 24 10 48 8b 7c 24 28 48 83 c7 48 e8 7d c7 15 0a e8 28 e8 37 00 fb 80 7c 24 1c 00 <4c> 8b b4 24 a0 00 00 00 4c 8b a4 24 98 00 00 00 48 8b 54 24 20 0f
RSP: 0018:ffffffff8e607a40 EFLAGS: 00000202
RAX: 0000000001c0862d RBX: ffffffff8e692ec0 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8dfac14f RDI: ffffffff8c28b660
RBP: dffffc0000000000 R08: ffffffff9030ccf7 R09: 1ffffffff206199e
R10: dffffc0000000000 R11: fffffbfff206199f R12: 1ffff110170c779c
R13: 0000000000000001 R14: 1ffff110170e779c R15: 0000000000000000
do_balance_callbacks kernel/sched/core.c:5018 [inline]
__balance_callbacks kernel/sched/core.c:5074 [inline]
finish_lock_switch kernel/sched/core.c:5123 [inline]
finish_task_switch+0x5dd/0xbe0 kernel/sched/core.c:5243
context_switch kernel/sched/core.c:5391 [inline]
__schedule+0x1829/0x5740 kernel/sched/core.c:7189
schedule_idle+0x51/0x90 kernel/sched/core.c:7309
do_idle+0x58a/0x5f0 kernel/sched/idle.c:381
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
rest_init+0x2de/0x300 init/main.c:762
start_kernel+0x38a/0x3e0 init/main.c:1220
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
rcu: rcu_preempt kthread starved for 10498 jiffies! g74401 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 3300 Comm: kworker/u8:8 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xfdf/0x13d0 kernel/smp.c:892
Code: 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 25 02 0c 00 eb 37 f3 90 43 0f b6 04 2c 84 c0 75 10 41 f7 06 01 00 00 00 <74> 1e e8 0a 02 0c 00 eb e5 44 89 f1 80 e1 07 80 c1 03 38 c1 7c e3
RSP: 0018:ffffc9000f2c7700 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff8880b873c148 RCX: ffff888032d99ec0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000f2c7840 R08: ffffffff9030ccf7 R09: 1ffffffff206199e
R10: dffffc0000000000 R11: fffffbfff206199f R12: 1ffff110170c8589
R13: dffffc0000000000 R14: ffff8880b8642c48 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125389000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2c4150 CR3: 000000000e74a000 CR4: 0000000000350ef0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057
on_each_cpu include/linux/smp.h:72 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline]
smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2983
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+0xab/0x290 mm/kfence/core.c:906
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245