rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=3adc/1/0x4000000000000000 softirq=22725/22726 fqs=5 rcu: (detected by 1, t=10502 jiffies, g=22261, q=1334 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6458 Comm: rm Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:lock_is_held_type+0x0/0x150 kernel/locking/lockdep.c:5925 Code: 3d 85 b2 88 04 48 c7 c6 73 ef 42 8e 67 48 0f b9 3a 90 eb ce 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 41 57 41 56 41 55 41 54 53 bb ff ff ff ff 83 3d d6 RSP: 0000:ffffc90000007d08 EFLAGS: 00000002 RAX: ffffffff89de65c2 RBX: 0000000000000001 RCX: 0000000000010000 RDX: ffff888031231f00 RSI: 00000000ffffffff RDI: ffff88807b2812c0 RBP: ffff88807b281300 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f90 R12: 0000000000000002 R13: ffff88807b281000 R14: ffff88807b281300 R15: dffffc0000000000 FS: 00007f03871b9c80(0000) GS:ffff888124f4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055574ff80008 CR3: 0000000079f52000 CR4: 00000000003526f0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0xe4/0xc80 net/sched/sch_taprio.c:932 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:229 [inline] RIP: 0010:unwind_next_frame+0x205/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: 6c 04 00 00 44 89 f8 4c 8d 2c 85 d8 bf 9d 91 4c 89 e8 48 c1 e8 03 42 0f b6 04 20 84 c0 4c 89 e3 0f 85 66 1d 00 00 45 8b 6d 00 <44> 89 f8 ff c0 4c 8d 24 85 d8 bf 9d 91 4c 89 e0 48 c1 e8 03 0f b6 RSP: 0000:ffffc900037bf440 EFLAGS: 00000246 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000080000000 RDX: 00000000000ad616 RSI: ffffffff8c4bdd60 RDI: ffffffff8c4bdd20 RBP: ffffffff8bd22329 R08: ffffffff8177927f R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c60 R12: dffffc0000000000 R13: 00000000001dedd1 R14: ffffc900037bf4e8 R15: 00000000000ad223 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_pages_mpol+0x212/0x380 mm/mempolicy.c:2490 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline] alloc_pages_noprof+0xac/0x2a0 mm/mempolicy.c:2581 pagetable_alloc_noprof include/linux/mm.h:3685 [inline] pmd_alloc_one_noprof include/asm-generic/pgalloc.h:143 [inline] __pmd_alloc+0x3a/0x5c0 mm/memory.c:6772 pmd_alloc include/linux/mm.h:3601 [inline] __handle_mm_fault mm/memory.c:6469 [inline] handle_mm_fault+0xe20/0x3080 mm/memory.c:6686 do_user_addr_fault+0xa4d/0x1340 arch/x86/mm/fault.c:1343 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0033:0x7f03873198d2 Code: f4 06 00 00 45 31 db 84 c0 0f 85 a3 05 00 00 48 8b 15 8a aa 13 00 49 29 c9 48 89 0d 58 a2 13 00 4d 01 d9 49 83 c9 01 4c 01 f2 <4c> 89 49 08 48 89 15 6b aa 13 00 4d 85 e4 0f 84 7b fd ff ff 49 83 RSP: 002b:00007ffccb0d0450 EFLAGS: 00010206 RAX: ffffffffffffffff RBX: 00007f0387453ac0 RCX: 000055574ff80000 RDX: 0000000000021000 RSI: 00007f0387453ac0 RDI: 0000000000000000 RBP: 0000000000000290 R08: 000055574ffa1000 R09: 0000000000021001 R10: 00007f0387453ac0 R11: 0000000000000000 R12: 0000000000000000 R13: 00007f0387453b20 R14: 0000000000000000 R15: 00000000000002b0 rcu: rcu_preempt kthread starved for 10492 jiffies! g22261 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 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: 6244 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x11e6/0x15f0 kernel/smp.c:912 Code: c0 75 7a 41 8b 1e 89 de 83 e6 01 31 ff e8 e2 22 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 8e 1e 0c 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 73 1e 0c RSP: 0018:ffffc90003417700 EFLAGS: 00000293 RAX: ffffffff81baf58d RBX: dffffc0000000000 RCX: ffff888030cebe00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003417860 R08: ffffffff9057a637 R09: 1ffffffff20af4c6 R10: dffffc0000000000 R11: fffffbfff20af4c7 R12: 1ffff110170c85fd R13: ffff8880b873c448 R14: ffff8880b8642fe8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812504f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f09898e7eb8 CR3: 000000000e946000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1077 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+0x5fd/0x1110 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:911 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 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