rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=5d64/1/0x4000000000000000 softirq=220875/220876 fqs=0 rcu: (detected by 0, t=10506 jiffies, g=249105, q=210 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 29428 Comm: syz.3.10029 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:memory_is_nonzero mm/kasan/generic.c:114 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:140 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x71/0x1e0 mm/kasan/generic.c:200 Code: 37 ff 48 89 fd 48 b8 00 00 00 00 00 fc ff df 4d 89 d1 48 c1 ed 03 49 c1 e9 03 48 01 c5 49 01 c1 48 89 e8 49 8d 59 01 48 89 da <48> 29 ea 48 83 fa 10 0f 8e db 00 00 00 41 89 eb 41 83 e3 07 0f 85 RSP: 0018:ffffc90000a08d58 EFLAGS: 00000086 RAX: fffffbfff3680fd7 RBX: fffffbfff3680fd8 RCX: ffffffff81e54493 RDX: fffffbfff3680fd8 RSI: 0000000000000004 RDI: ffffffff9b407eb8 RBP: fffffbfff3680fd7 R08: 0000000000000000 R09: fffffbfff3680fd7 R10: ffffffff9b407ebb R11: ffffc90000a08ff8 R12: 0000000000000001 R13: dffffc0000000000 R14: ffff888022ec6300 R15: 1ffff920001411b8 FS: 00007f9ae9b726c0(0000) GS:ffff888124418000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9ae8e4f270 CR3: 000000002b354000 CR4: 00000000003526f0 Call Trace: instrument_atomic_read include/linux/instrumented.h:82 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] queued_spin_is_locked include/asm-generic/qspinlock.h:57 [inline] debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline] do_raw_spin_unlock+0x53/0x1e0 kernel/locking/spinlock_debug.c:141 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:177 [inline] _raw_spin_unlock_irqrestore+0x22/0x80 kernel/locking/spinlock.c:198 debug_object_deactivate+0x2e4/0x3b0 lib/debugobjects.c:943 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:2000 [inline] __hrtimer_run_queues+0x2e9/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 56 4d 4b f6 48 89 df e8 de 9c 4b f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 ae 3a f6 65 8b 05 ae d8 76 08 85 c0 74 16 5b RSP: 0018:ffffc90011adfad8 EFLAGS: 00000246 RAX: 0000000000000046 RBX: ffff8880203954f8 RCX: ffffffff8211aa2f RDX: 0000000000000000 RSI: ffffffff8c1d2780 RDI: ffffffff8b99a792 RBP: 0000000000000283 R08: 0000000000000000 R09: fffffbfff21b44f2 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: ffff888020394a98 R14: ffff8880203954f8 R15: ffff888020394a80 class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:571 [inline] try_to_wake_up+0xf20/0x1c90 kernel/sched/core.c:4292 wake_up_process kernel/sched/core.c:4547 [inline] wake_up_q+0xa1/0x130 kernel/sched/core.c:1173 futex_wake+0x4f4/0x5e0 kernel/futex/waitwake.c:225 do_futex+0x2b2/0x440 kernel/futex/syscalls.c:138 __do_sys_futex kernel/futex/syscalls.c:210 [inline] __se_sys_futex kernel/futex/syscalls.c:191 [inline] __x64_sys_futex+0x34f/0x4d0 kernel/futex/syscalls.c:191 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9ae8d9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9ae9b720e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f9ae9015fa8 RCX: 00007f9ae8d9ce59 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f9ae9015fac RBP: 00007f9ae9015fa0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9ae9016038 R14: 00007ffdc1dbfd70 R15: 00007ffdc1dbfe58 rcu: rcu_preempt kthread starved for 10506 jiffies! g249105 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:28232 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7322 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 0 UID: 0 PID: 23546 Comm: kworker/u8:25 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x58e/0x16c0 kernel/smp.c:892 Code: 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 b9 95 0c 00 f3 90 41 0f b6 45 00 <41> 38 c4 7c 08 84 c0 0f 85 2c 0f 00 00 8b 45 08 31 ff 83 e0 01 41 RSP: 0018:ffffc90002fe7878 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fcc98d RDX: ffff888055298000 RSI: ffffffff81fcc967 RDI: ffff888055298000 RBP: ffff8880b85410c0 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a8219 R14: 0000000000000001 R15: ffff8880b843c700 FS: 0000000000000000(0000) GS:ffff888124318000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2da21ff8 CR3: 000000000e592000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 00000000be70000e DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x40/0x90 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+0x337/0xc60 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:906 [inline] toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:898 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245