rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=0764/1/0x4000000000000000 softirq=78405/78406 fqs=17 (detected by 0, t=10506 jiffies, g=122449, q=289 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 20564 Comm: syz.3.4603 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:lock_acquire+0x1b6/0x4a0 kernel/locking/lockdep.c:5662 Code: f7 c6 00 02 00 00 41 0f 94 c1 48 8b 7c 24 20 8b 74 24 14 89 da 48 8b 4c 24 28 4c 8b 44 24 30 6a 00 6a 00 ff 75 10 ff 74 24 30 25 04 00 00 48 83 c4 20 48 c7 c7 20 2b 8c 8a e8 25 bc c9 08 b8 RSP: 0018:ffffc900001e0ac0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff96eb97e8 RBP: ffffc900001e0be8 R08: 0000000000000001 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff1c3ff7e R12: 0000000000000001 R13: 1ffff9200003c168 R14: 0000000000000046 R15: dffffc0000000000 FS: 00007f5c968da6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5c95985fc0 CR3: 000000002f27f000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162 debug_object_activate+0x68/0x4f0 lib/debugobjects.c:698 debug_hrtimer_activate kernel/time/hrtimer.c:448 [inline] debug_activate kernel/time/hrtimer.c:503 [inline] enqueue_hrtimer+0x30/0x3f0 kernel/time/hrtimer.c:1105 __run_hrtimer kernel/time/hrtimer.c:1764 [inline] __hrtimer_run_queues+0x685/0xd50 kernel/time/hrtimer.c:1811 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194 Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 7f ee 20 f7 65 8b 05 80 60 ca 75 85 c0 74 3c 48 c7 04 24 0e 36 RSP: 0018:ffffc900033c7c80 EFLAGS: 00000206 RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: 9f1faed3bc6d0200 RDX: dffffc0000000000 RSI: ffffffff8a8c19a0 RDI: 0000000000000001 RBP: ffffc900033c7d10 R08: ffffffff8cb470c3 R09: 1ffffffff1968e18 R10: dffffc0000000000 R11: fffffbfff1968e19 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff8cb470c0 R15: 1ffff92000678f90 do_settimeofday64+0x5ac/0x760 kernel/time/timekeeping.c:1342 __do_sys_clock_settime kernel/time/posix-timers.c:1125 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1113 [inline] __x64_sys_clock_settime+0x25a/0x2a0 kernel/time/posix-timers.c:1113 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f5c9599ce59 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:00007f5c968da028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007f5c95c15fa0 RCX: 00007f5c9599ce59 RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000 RBP: 00007f5c95a32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5c95c16038 R14: 00007f5c95c15fa0 R15: 00007ffc05f8cf28 rcu: rcu_preempt kthread starved for 10370 jiffies! g122449 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:27760 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 12626 Comm: kworker/u4:15 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline] RIP: 0010:smp_call_function_many_cond+0xea2/0x1290 kernel/smp.c:998 Code: 00 00 00 41 8b 1f 89 de 83 e6 01 31 ff e8 f6 f6 0a 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 82 f3 0a 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 67 f3 0a RSP: 0018:ffffc90003a67800 EFLAGS: 00000293 RAX: ffffffff81779349 RBX: dffffc0000000000 RCX: ffff888025bc9dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003a67960 R08: ffffffff90afa247 R09: 1ffffffff215f448 R10: dffffc0000000000 R11: fffffbfff215f449 R12: 1ffff110171e81d9 R13: ffff8880b8e3bbc0 R14: 0000000000000001 R15: ffff8880b8f40ec8 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8c25800218 CR3: 000000000c88e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1574 [inline] text_poke_bp_batch+0x2b7/0x850 arch/x86/kernel/alternative.c:1774 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207 static_key_enable+0x16/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xba/0x470 mm/kfence/core.c:821 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295