rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 ticks this GP) idle=37d4/1/0x4000000000000000 softirq=84815/84815 fqs=2 rcu: (detected by 0, t=10502 jiffies, g=129329, q=194 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6612 Comm: kworker/1:9 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_power_efficient gc_worker RIP: 0010:check_preemption_disabled+0x1/0x110 lib/smp_processor_id.c:13 Code: e9 6e ff ff ff cc cc cc cc f3 0f 1e fa 48 c7 c7 c0 f9 1c 8b 48 c7 c6 00 fa 1c 8b eb 0c 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 RSP: 0018:ffffc900001f0b30 EFLAGS: 00000092 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81681b46 RDX: 0000000000000000 RSI: ffffffff8acadce0 RDI: ffffffff8b1cfa20 RBP: ffffc900001f0c48 R08: dffffc0000000000 R09: 1ffffffff223cea0 R10: dffffc0000000000 R11: fffffbfff223cea1 R12: 1ffff9200003e174 R13: ffffffff974a6738 R14: 0000000000000046 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8d86227dac CR3: 0000000041af9000 CR4: 00000000003506e0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline] lock_acquire+0x1ae/0x420 kernel/locking/lockdep.c:5756 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162 debug_object_deactivate+0x67/0x380 lib/debugobjects.c:802 debug_hrtimer_deactivate kernel/time/hrtimer.c:455 [inline] __run_hrtimer kernel/time/hrtimer.c:1722 [inline] __hrtimer_run_queues+0x2cc/0xc10 kernel/time/hrtimer.c:1818 hrtimer_interrupt+0x39d/0x980 kernel/time/hrtimer.c:1880 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc90003237940 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 2074bfe0e8055c00 RDX: 0000000000000000 RSI: ffffffff8acadce0 RDI: ffffffff8b1cfa20 RBP: ffffc90003237a48 R08: dffffc0000000000 R09: 1ffffffff223cea0 R10: dffffc0000000000 R11: fffffbfff223cea1 R12: 1ffff92000646f34 R13: ffffffff8d131da0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] gc_worker+0x28a/0x14a0 net/netfilter/nf_conntrack_core.c:1502 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: rcu_preempt kthread starved for 10498 jiffies! g129329 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:27128 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 12528 Comm: kworker/u4:27 Not tainted syzkaller #0 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:311 [inline] RIP: 0010:smp_call_function_many_cond+0xd85/0x1190 kernel/smp.c:855 Code: 45 8b 34 24 44 89 f6 83 e6 01 31 ff e8 54 f1 0a 00 41 83 e6 01 49 be 00 00 00 00 00 fc ff df 75 07 e8 8f ed 0a 00 eb 38 f3 90 <42> 0f b6 04 33 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 73 ed RSP: 0018:ffffc900048bf780 EFLAGS: 00000293 RAX: ffffffff817bf7fd RBX: 1ffff110171e82bd RCX: ffff88802faf9e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900048bf900 R08: ffffffff911e7507 R09: 1ffffffff223cea0 R10: dffffc0000000000 R11: fffffbfff223cea1 R12: ffff8880b8f415e8 R13: ffff8880b8e3d3c0 R14: dffffc0000000000 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9fa59556b8 CR3: 000000000cf32000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000001800 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2222 [inline] text_poke_bp_batch+0x31e/0x980 arch/x86/kernel/alternative.c:2432 text_poke_flush arch/x86/kernel/alternative.c:2623 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207 static_key_enable+0x1a/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xa8/0x260 mm/kfence/core.c:847 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293