rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16 rcu: (detected by 0, t=10502 jiffies, g=17073, q=9813 ncpus=2) task:ktimers/0 state:R running task stack:21464 pid:16 tgid:16 ppid:2 task_flags:0x4208040 flags:0x00080000 Call Trace: sched_show_task+0x4aa/0x5f0 kernel/sched/core.c:8139 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline] print_other_cpu_stall+0xfca/0x1380 kernel/rcu/tree_stall.h:681 check_cpu_stall kernel/rcu/tree_stall.h:856 [inline] rcu_pending kernel/rcu/tree.c:3679 [inline] rcu_sched_clock_irq+0x939/0x1050 kernel/rcu/tree.c:2716 update_process_times+0x234/0x2d0 kernel/time/timer.c:2475 tick_sched_handle kernel/time/tick-sched.c:298 [inline] tick_nohz_handler+0x42b/0x770 kernel/time/tick-sched.c:319 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x3bc/0xb10 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x455/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 9d 1d 81 f6 f7 c3 00 02 00 00 74 05 e8 10 c2 ac f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 44 ad 73 f6 65 8b 05 dd 92 4a 07 85 c0 74 18 5b 41 5e e9 01 3c RSP: 0018:ffffc90000157ba0 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000246 RCX: 0000000080000001 RDX: 0000000000000002 RSI: ffffffff8d6042a7 RDI: 0000000000000001 RBP: ffff8880b8828950 R08: ffffffff8f88e1f7 R09: 1ffffffff1f11c3e R10: dffffc0000000000 R11: fffffbfff1f11c3f R12: ffffffff89301270 R13: 1ffff11017105122 R14: ffff8880b8828540 R15: ffff8880405c5440 __run_hrtimer kernel/time/hrtimer.c:1926 [inline] __hrtimer_run_queues+0x305/0xb10 kernel/time/hrtimer.c:1994 hrtimer_run_softirq+0x18f/0x260 kernel/time/hrtimer.c:2011 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1151 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 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: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g17073 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=8610 rcu: rcu_preempt kthread starved for 10502 jiffies! g17073 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27768 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x1681/0x54c0 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 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: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 9d 1d 81 f6 f7 c3 00 02 00 00 74 05 e8 10 c2 ac f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 44 ad 73 f6 65 8b 05 dd 92 4a 07 85 c0 74 18 5b 41 5e e9 01 3c RSP: 0018:ffffc90000157ba0 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000246 RCX: 0000000080000001 RDX: 0000000000000002 RSI: ffffffff8d6042a7 RDI: 0000000000000001 RBP: ffff8880b8828950 R08: ffffffff8f88e1f7 R09: 1ffffffff1f11c3e R10: dffffc0000000000 R11: fffffbfff1f11c3f R12: ffffffff89301270 R13: 1ffff11017105122 R14: ffff8880b8828540 R15: ffff8880405c5440 FS: 0000000000000000(0000) GS:ffff888126179000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9a4ffa0574 CR3: 0000000035f42000 CR4: 00000000003526f0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1926 [inline] __hrtimer_run_queues+0x305/0xb10 kernel/time/hrtimer.c:1994 hrtimer_run_softirq+0x18f/0x260 kernel/time/hrtimer.c:2011 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1151 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 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