rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=093c/1/0x4000000000000000 softirq=17312/17315 fqs=3 rcu: (detected by 1, t=10502 jiffies, g=8281, q=1211 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6101 Comm: syz-executor.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:preempt_count_add+0x0/0x1a0 kernel/sched/core.c:5816 Code: c1 7c 97 48 8b 3c 24 e8 3e e8 90 00 eb 8c e9 f1 fe ff ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 53 49 bf 00 00 00 00 00 fc ff df 48 c7 c0 RSP: 0018:ffffc90000007bf8 EFLAGS: 00000046 RAX: f3f3f300f1f1f1f1 RBX: ffffffff99cc5670 RCX: 000000000000dca8 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffffc90000007c98 R08: ffffc90000007cbf R09: 0000000000000000 R10: ffffc90000007cb0 R11: fffff52000000f98 R12: dffffc0000000000 R13: dffffc0000000000 R14: 0000000000000802 R15: 1ffff92000000f80 FS: 00007f52f7fa96c0(0000) GS:ffff888125c53000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000600 CR3: 00000000756de000 CR4: 00000000003526f0 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:109 [inline] _raw_spin_lock_irqsave+0x8c/0xf0 kernel/locking/spinlock.c:162 debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:490 __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:queue_work_on+0x1f7/0x270 kernel/workqueue.c:2395 Code: 4d 85 ff 75 16 e8 79 a8 35 00 eb 15 e8 72 a8 35 00 e8 7d 76 e7 09 4d 85 ff 74 ea e8 63 a8 35 00 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 04 2e 00 00 00 00 66 43 c7 44 2e 09 00 00 43 c6 44 2e 0b 00 RSP: 0018:ffffc9000492faa0 EFLAGS: 00000293 RAX: ffffffff818a01ad RBX: ffffffff8e15f001 RCX: ffff88807db50000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000492fb90 R08: ffffffff8fa24a37 R09: 1ffffffff1f44946 R10: dffffc0000000000 R11: fffffbfff1f44947 R12: 0000000000000000 R13: dffffc0000000000 R14: 1ffff92000925f5c R15: 0000000000000200 do_adjtimex+0x926/0xb20 kernel/time/timekeeping.c:2749 do_clock_adjtime kernel/time/posix-timers.c:1162 [inline] __do_sys_clock_adjtime kernel/time/posix-timers.c:1174 [inline] __se_sys_clock_adjtime kernel/time/posix-timers.c:1165 [inline] __x64_sys_clock_adjtime+0x1f7/0x2b0 kernel/time/posix-timers.c:1165 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f52f727cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f52f7fa90c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f52f739bf80 RCX: 00007f52f727cae9 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000000 RBP: 00007f52f72c847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f52f739bf80 R15: 00007fff233726c8 rcu: rcu_preempt kthread starved for 10496 jiffies! g8281 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1742/0x4c70 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 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+0x3f9/0x770 arch/x86/kernel/process.c:148 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: 48 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 a6 62 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 51 5e 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 35 5e RSP: 0000:ffffc90000b87660 EFLAGS: 00000293 RAX: ffffffff81b44bdb RBX: 1ffff110170c8319 RCX: ffff88801a5e8000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000b877e0 R08: ffffffff8fa24a37 R09: 1ffffffff1f44946 R10: dffffc0000000000 R11: fffffbfff1f44947 R12: ffff8880b86418c8 R13: dffffc0000000000 R14: ffff8880b873b040 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125d53000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7178146ee0 CR3: 000000000df36000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245