rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=9389, q=958 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10498 (4294962885-4294952387), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10499 jiffies! g9389 f0x2 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:28752 pid:17 tgid:17 ppid:2 flags:0x00004008 Call Trace: sched_show_task kernel/sched/core.c:9146 [inline] sched_show_task+0x42e/0x650 kernel/sched/core.c:9120 rcu_check_gp_kthread_starvation+0x19f/0x450 kernel/rcu/tree_stall.h:548 print_other_cpu_stall kernel/rcu/tree_stall.h:656 [inline] check_cpu_stall kernel/rcu/tree_stall.h:796 [inline] rcu_pending kernel/rcu/tree.c:3891 [inline] rcu_sched_clock_irq+0x2269/0x3150 kernel/rcu/tree.c:2259 update_process_times+0x17b/0x220 kernel/time/timer.c:2071 tick_sched_handle+0x8e/0x170 kernel/time/tick-sched.c:255 tick_nohz_highres_handler+0xe9/0x110 kernel/time/tick-sched.c:1516 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x647/0xc20 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1065 [inline] __sysvec_apic_timer_interrupt+0x105/0x400 arch/x86/kernel/apic/apic.c:1082 sysvec_apic_timer_interrupt+0x43/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:div_u64_rem include/linux/math64.h:29 [inline] RIP: 0010:div_u64 include/linux/math64.h:130 [inline] RIP: 0010:pie_calculate_probability+0x284/0x850 net/sched/sch_pie.c:345 Code: 89 c5 48 89 6c 24 38 e8 fa 47 e6 f8 47 8d 24 a4 31 d2 4c 89 ff 43 8d 0c 24 49 c1 ee 02 48 b8 ff ff ff ff ff ff ff 00 48 f7 f1 <48> 89 c5 48 89 c6 48 c1 eb 02 49 89 cc e8 da 42 e6 f8 49 39 ef 73 RSP: 0018:ffffc900001f0bb8 EFLAGS: 00000207 RAX: 0000068db8bac710 RBX: 000000002af31dc4 RCX: 0000000000002710 RDX: 0000000000001eff RSI: ffffffff88a129d6 RDI: 0000000000000000 RBP: 00004189374bc6a7 R08: 0000000000000005 R09: 00000000000f4240 R10: 00000000000003e8 R11: 0000000000000002 R12: 0000000000001388 R13: 0000000000000004 R14: 000000000112e0be R15: 0000000000000000 fq_pie_timer+0x215/0x5a0 net/sched/sch_fq_pie.c:391 call_timer_fn+0x193/0x590 kernel/time/timer.c:1700 expire_timers kernel/time/timer.c:1751 [inline] __run_timers+0x764/0xb20 kernel/time/timer.c:2022 run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035 __do_softirq+0x21a/0x8de kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:finish_task_switch.isra.0+0x223/0xca0 kernel/sched/core.c:5250 Code: 0a 00 00 44 8b 0d 35 8b be 0d 45 85 c9 0f 85 c0 01 00 00 48 89 df e8 cc f8 ff ff e8 57 47 33 00 fb 65 48 8b 1c 25 c0 bc 03 00 <48> 8d bb d8 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc90000167a08 EFLAGS: 00000206 RAX: 000000000001e735 RBX: ffff888017e48000 RCX: 1ffffffff1e320a9 RDX: 0000000000000000 RSI: ffffffff8accaec0 RDI: ffffffff8b2efba0 RBP: ffffc90000167a50 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff8f1937d7 R11: 0000000000000000 R12: ffff8880b993d478 R13: ffff888026c53b80 R14: 0000000000000000 R15: ffff8880b993c700 context_switch kernel/sched/core.c:5379 [inline] __schedule+0xee3/0x5af0 kernel/sched/core.c:6688 __schedule_loop kernel/sched/core.c:6763 [inline] schedule+0xe9/0x270 kernel/sched/core.c:6778 schedule_timeout+0x137/0x290 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x1ec/0xb10 kernel/rcu/tree.c:1631 rcu_gp_kthread+0x24b/0x380 kernel/rcu/tree.c:1830 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 17 Comm: rcu_preempt Not tainted 6.7.0-rc6-syzkaller-00157-g7c5e046bdcb2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 RIP: 0010:div_u64_rem include/linux/math64.h:29 [inline] RIP: 0010:div_u64 include/linux/math64.h:130 [inline] RIP: 0010:pie_calculate_probability+0x284/0x850 net/sched/sch_pie.c:345 Code: 89 c5 48 89 6c 24 38 e8 fa 47 e6 f8 47 8d 24 a4 31 d2 4c 89 ff 43 8d 0c 24 49 c1 ee 02 48 b8 ff ff ff ff ff ff ff 00 48 f7 f1 <48> 89 c5 48 89 c6 48 c1 eb 02 49 89 cc e8 da 42 e6 f8 49 39 ef 73 RSP: 0018:ffffc900001f0bb8 EFLAGS: 00000207 RAX: 0000068db8bac710 RBX: 000000002af31dc4 RCX: 0000000000002710 RDX: 0000000000001eff RSI: ffffffff88a129d6 RDI: 0000000000000000 RBP: 00004189374bc6a7 R08: 0000000000000005 R09: 00000000000f4240 R10: 00000000000003e8 R11: 0000000000000002 R12: 0000000000001388 R13: 0000000000000004 R14: 000000000112e0be R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555556c89ca8 CR3: 0000000078bae000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: fq_pie_timer+0x215/0x5a0 net/sched/sch_fq_pie.c:391 call_timer_fn+0x193/0x590 kernel/time/timer.c:1700 expire_timers kernel/time/timer.c:1751 [inline] __run_timers+0x764/0xb20 kernel/time/timer.c:2022 run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035 __do_softirq+0x21a/0x8de kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:finish_task_switch.isra.0+0x223/0xca0 kernel/sched/core.c:5250 Code: 0a 00 00 44 8b 0d 35 8b be 0d 45 85 c9 0f 85 c0 01 00 00 48 89 df e8 cc f8 ff ff e8 57 47 33 00 fb 65 48 8b 1c 25 c0 bc 03 00 <48> 8d bb d8 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc90000167a08 EFLAGS: 00000206 RAX: 000000000001e735 RBX: ffff888017e48000 RCX: 1ffffffff1e320a9 RDX: 0000000000000000 RSI: ffffffff8accaec0 RDI: ffffffff8b2efba0 RBP: ffffc90000167a50 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff8f1937d7 R11: 0000000000000000 R12: ffff8880b993d478 R13: ffff888026c53b80 R14: 0000000000000000 R15: ffff8880b993c700 context_switch kernel/sched/core.c:5379 [inline] __schedule+0xee3/0x5af0 kernel/sched/core.c:6688 __schedule_loop kernel/sched/core.c:6763 [inline] schedule+0xe9/0x270 kernel/sched/core.c:6778 schedule_timeout+0x137/0x290 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x1ec/0xb10 kernel/rcu/tree.c:1631 rcu_gp_kthread+0x24b/0x380 kernel/rcu/tree.c:1830 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242