sched: DL replenish lagged too much rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=32c4/1/0x4000000000000000 softirq=18799/18804 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5836/1:b..l rcu: (detected by 0, t=10506 jiffies, g=14677, q=2181 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 984 Comm: kworker/1:2 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: rcu_gp process_srcu RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x5/0x18 Code: 41 58 5f 5e 5a 59 e9 ca 3e 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 52 01 00 00 00 31 d2 f0 0f b0 17 75 06 5a e9 98 3e 00 00 56 0f b6 RSP: 0018:ffffc90000a08c58 EFLAGS: 00000086 RAX: 1ffffffff1bb5187 RBX: ffff8880b8927ac0 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880b8927ac0 RBP: 1ffff11017124f59 R08: ffff8880b8927ac3 R09: 1ffff11017124f58 R10: dffffc0000000000 R11: ffffed1017124f59 R12: dffffc0000000000 R13: 1ffff11017124f5a R14: ffff8880b8927ad0 R15: ffff8880b8927ac8 FS: 0000000000000000(0000) GS:ffff88812623c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb495212700 CR3: 00000000764fa000 CR4: 00000000003526f0 Call Trace: pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:562 [inline] queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline] do_raw_spin_unlock+0x122/0x240 kernel/locking/spinlock_debug.c:142 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock_irqrestore+0x78/0x110 kernel/locking/spinlock.c:194 __run_hrtimer kernel/time/hrtimer.c:1773 [inline] __hrtimer_run_queues+0x408/0xc60 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+0x10b/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:697 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202 Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 4a 8b 54 f6 48 89 df e8 a2 22 55 f6 e8 9d eb 7e f6 fb bf 01 00 00 00 b2 19 47 f6 65 8b 05 3b 68 25 07 85 c0 74 07 5b c3 cc cc cc cc RSP: 0018:ffffc9000394fa50 EFLAGS: 00000282 RAX: 4f501dc6518b0200 RBX: ffff8880b89397c0 RCX: 4f501dc6518b0200 RDX: 0000000000000000 RSI: ffffffff8d70d52a RDI: 0000000000000001 RBP: ffffc9000394fc50 R08: ffffffff8f7cdc77 R09: 1ffffffff1ef9b8e R10: dffffc0000000000 R11: fffffbfff1ef9b8f R12: ffff8880b89397c0 R13: ffff88801d2ed2d0 R14: dffffc0000000000 R15: 0000000001800000 process_one_work kernel/workqueue.c:3232 [inline] process_scheduled_works+0x8ce/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz-executor state:R running task stack:21304 pid:5836 tgid:5836 ppid:5822 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7113 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7137 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] wp_page_copy mm/memory.c:3780 [inline] do_wp_page+0x1d1d/0x5800 mm/memory.c:4140 handle_pte_fault mm/memory.c:6193 [inline] __handle_mm_fault+0x1033/0x5400 mm/memory.c:6318 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6487 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f2fb9b4d9ff RSP: 002b:00007ffc6969b120 EFLAGS: 00010206 RAX: 0000000000006a41 RBX: 0000000000008040 RCX: 0000555562e29590 RDX: 0000000000008041 RSI: 0000555562e315c0 RDI: 0000000000000004 RBP: 00007f2fb9db7cc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001000 R11: 0000000000000802 R12: 0000000000008030 R13: 0000000000000076 R14: 00007f2fb9db7d20 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10506 jiffies! g14677 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:27224 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+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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: 1138 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd38/0x12d0 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 b6 73 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 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 45 6f 0b 00 eb e4 44 RSP: 0018:ffffc90003b5f640 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff11017127ffd RCX: ffff8880267d0000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003b5f7c0 R08: ffffffff8f7cdc77 R09: 1ffffffff1ef9b8e R10: dffffc0000000000 R11: fffffbfff1ef9b8f R12: ffff8880b893ffe8 R13: dffffc0000000000 R14: ffff8880b883b240 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812613c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcbba63688 CR3: 000000000dd38000 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:2713 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2923 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+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245