rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=891c/1/0x4000000000000000 softirq=50747/50748 fqs=1
rcu: (detected by 1, t=10506 jiffies, g=42485, q=220 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9891 Comm: syz.3.771 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:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4854 [inline]
RIP: 0010:__lock_acquire+0x35f/0x2cf0 kernel/locking/lockdep.c:5187
Code: 09 d4 41 09 cc 41 09 dc 45 89 64 c7 20 41 89 7c c7 24 4c 89 7c 24 20 4d 8d 2c c7 41 81 e4 ff 1f 00 00 4c 0f a3 25 91 ff 08 12 <73> 15 49 69 c4 c8 00 00 00 48 8d 80 b0 73 48 93 4c 8b 74 24 08 eb
RSP: 0018:ffffc90000007a88 EFLAGS: 00000003
RAX: 000000000000000f RBX: 0000000000024000 RCX: 0000000000000007
RDX: 0000000000080000 RSI: 0000000000004000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff89741ce8 R09: ffffffff8e13f2e0
R10: dffffc0000000000 R11: ffffed100ad6b856 R12: 0000000000000007
R13: ffff888058fe2a28 R14: ffff888058fe1e80 R15: ffff888058fe29b0
FS: 00007fd1c7a546c0(0000) GS:ffff888125c25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd1bd7ff000 CR3: 0000000075d88000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
advance_sched+0xa14/0xc90 net/sched/sch_taprio.c:991
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x51c/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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 0b 44 69 f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 23 bb 30 f6 65 8b 05 7c 60 3f 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc9000b7df600 EFLAGS: 00000206
RAX: b8f3a83515e07100 RBX: 0000000000000a06 RCX: b8f3a83515e07100
RDX: 0000000000000006 RSI: ffffffff8d997e54 RDI: 0000000000000001
RBP: ffffc9000b7df690 R08: ffffffff8fa22f77 R09: 1ffffffff1f445ee
R10: dffffc0000000000 R11: fffffbfff1f445ef R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88801cef9958 R15: 1ffff920016fbec0
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
unlock_page_lruvec_irqrestore include/linux/memcontrol.h:1481 [inline]
folio_batch_move_lru+0x37e/0x420 mm/swap.c:178
__folio_batch_add_and_move+0x51c/0xc40 mm/swap.c:196
shmem_alloc_and_add_folio+0xca0/0xf40 mm/shmem.c:2003
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2568
shmem_get_folio mm/shmem.c:2674 [inline]
shmem_write_begin+0x16c/0x330 mm/shmem.c:3327
generic_perform_write+0x2c5/0x900 mm/filemap.c:4314
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3502
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+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd1c6b8e1ff
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:00007fd1c7a53df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007fd1c6b8e1ff
RDX: 0000000001000000 RSI: 00007fd1bc800000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000972a
R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000003
R13: 00007fd1c7a53ef0 R14: 00007fd1c7a53eb0 R15: 00007fd1bc800000
rcu: rcu_preempt kthread starved for 10500 jiffies! g42485 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:27168 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
__schedule_loop kernel/sched/core.c:6948 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6963
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
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 80 Comm: kworker/u8:5 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_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 aa a6 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 55 a2 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 39 a2
RSP: 0018:ffffc900023df660 EFLAGS: 00000293
RAX: ffffffff81b61627 RBX: 1ffff110170c85d1 RCX: ffff88801cb5bd00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900023df7e0 R08: ffffffff8fa22f77 R09: 1ffffffff1f445ee
R10: dffffc0000000000 R11: fffffbfff1f445ef R12: ffff8880b8642e88
R13: dffffc0000000000 R14: ffff8880b873bd40 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5c8f5d9f98 CR3: 000000000df38000 CR4: 00000000003526f0
Call Trace:
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+0x93a/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
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