sched: DL replenish lagged too much rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=882c/1/0x4000000000000000 softirq=16170/16173 fqs=4 rcu: (detected by 0, t=10502 jiffies, g=11305, q=634 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6110 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:lock_acquire+0x15c/0x360 kernel/locking/lockdep.c:5871 Code: ff ff ff 65 0f c1 05 63 c0 ad 10 83 f8 01 0f 85 c9 00 00 00 48 c7 44 24 30 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 <0f> 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 db RSP: 0018:ffffc90000a08c00 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 42fe20267759f400 RDX: 0000000000000000 RSI: ffffffff8d6f55e3 RDI: ffffffff8b9eea60 RBP: ffffffff81ac5432 R08: 0000000000000000 R09: ffffffff81ac5432 R10: dffffc0000000000 R11: fffffbfff1eb7dc7 R12: 0000000000000000 R13: ffff8880b8927ad8 R14: 0000000000000001 R15: 0000000000000046 FS: 00007fb6b834ac80(0000) GS:ffff888126488000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb6b85ae7e8 CR3: 00000000336c0000 CR4: 00000000003526f0 Call Trace: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:170 __run_hrtimer kernel/time/hrtimer.c:1781 [inline] __hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 db 7f ad 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900030a72e8 EFLAGS: 00000206 RAX: 42fe20267759f400 RBX: 0000000000000001 RCX: 42fe20267759f400 RDX: 0000000000000000 RSI: ffffffff8d6f55e3 RDI: ffffffff8b9eea60 RBP: ffffffff820bcaa3 R08: 0000000000000000 R09: ffffffff820bcaa3 R10: dffffc0000000000 R11: fffff52000614e54 R12: 0000000000000000 R13: ffff8880327b12b8 R14: 0000000000000001 R15: 0000000000000246 _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378 copy_pte_range mm/memory.c:1254 [inline] copy_pmd_range+0x6d3/0x7f00 mm/memory.c:1389 copy_pud_range mm/memory.c:1426 [inline] copy_p4d_range mm/memory.c:1450 [inline] copy_page_range+0xc14/0x1270 mm/memory.c:1538 dup_mmap+0xf4c/0x1b10 mm/mmap.c:1834 dup_mm kernel/fork.c:1489 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1541 copy_process+0x1706/0x3c00 kernel/fork.c:2181 kernel_clone+0x21e/0x840 kernel/fork.c:2609 __do_sys_clone kernel/fork.c:2750 [inline] __se_sys_clone kernel/fork.c:2734 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2734 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: 0033:0x7fb6b84e4636 Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffef330c790 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffef330c798 RCX: 00007fb6b84e4636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 000055897f71ee60 R08: 0000000000000000 R09: 0000000000000000 R10: 00007fb6b834af50 R11: 0000000000000246 R12: 000055897f720f70 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10480 jiffies! g11305 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:27256 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 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+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 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: 3455 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 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 96 73 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 41 6f 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 25 6f RSP: 0018:ffffc9000c287660 EFLAGS: 00000293 RAX: ffffffff81b2f01b RBX: 1ffff11017127ff5 RCX: ffff888030900000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000c2877e0 R08: ffffffff8f5bee37 R09: 1ffffffff1eb7dc6 R10: dffffc0000000000 R11: fffffbfff1eb7dc7 R12: ffff8880b893ffa8 R13: dffffc0000000000 R14: ffff8880b883b200 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888126388000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb6b86b4368 CR3: 000000000db36000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 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:852 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245