sched: DL replenish lagged too much rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17232/1:b..l P17234/1:b..l rcu: (detected by 0, t=10502 jiffies, g=92985, q=1247 ncpus=2) task:syz.3.2523 state:R running task stack:27016 pid:17234 tgid:17233 ppid:16762 task_flags:0x40054c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7113 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+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1885 [inline] zap_pmd_range mm/memory.c:1947 [inline] zap_pud_range mm/memory.c:1976 [inline] zap_p4d_range mm/memory.c:1997 [inline] unmap_page_range+0xf71/0x41b0 mm/memory.c:2018 unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:2061 unmap_vmas+0x218/0x470 mm/memory.c:2105 exit_mmap+0x1b2/0xb90 mm/mmap.c:1280 __mmput+0x12a/0x410 kernel/fork.c:1133 mmput+0x62/0x70 kernel/fork.c:1156 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:954 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107 get_signal+0x2671/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8bc1d8f6c9 RSP: 002b:00007f8bc2c6a0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000000 RBX: 00007f8bc1fe5fa8 RCX: 00007f8bc1d8f6c9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8bc1fe5fa8 RBP: 00007f8bc1fe5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8bc1fe6038 R14: 00007ffcb8122bd0 R15: 00007ffcb8122cb8 task:syz-executor state:R running task stack:25912 pid:17232 tgid:17232 ppid:5818 task_flags:0x400000 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256 irqentry_exit+0x36/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5893 Code: 0f c1 05 38 24 09 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 4d e2 08 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41 RSP: 0018:ffffc90003d37470 EFLAGS: 00000206 RAX: 09e713b2bb022800 RBX: ffffffff8e3c45e0 RCX: ffffc90003d3747c RDX: 0000000000000000 RSI: ffffffff8da033a0 RDI: ffffffff8bf075c0 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000006280 R12: ffffffff816bb704 R13: 0000000000000206 R14: ffff88805b3edac0 R15: 0000000000000001 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479 __unwind_start+0x45f/0x7f0 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0x100 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __set_page_owner+0x91/0x560 mm/page_owner.c:332 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline] alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2507 vm_area_alloc_pages mm/vmalloc.c:3647 [inline] __vmalloc_area_node mm/vmalloc.c:3724 [inline] __vmalloc_node_range_noprof+0x6f8/0x1480 mm/vmalloc.c:3897 vmalloc_user_noprof+0x9e/0xe0 mm/vmalloc.c:4050 kcov_ioctl+0x4c/0x730 kernel/kcov.c:716 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f377218f2cb RSP: 002b:00007fffd2918ed0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000080000 RCX: 00007f377218f2cb RDX: 0000000000080000 RSI: ffffffff80086301 RDI: 00000000000000dd RBP: 00007f37723e64e8 R08: 00000000000000da R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000003 R14: 00007fffd2919218 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10571 jiffies! g92985 f0x0 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:28136 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G U W L XTNJ syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [W]=WARN, [L]=SOFTLOCKUP, [X]=AUX, [T]=RANDSTRUCT, [N]=TEST, [J]=FWCTL Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 77 6f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 94 2c 00 fb f4 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6 RAX: 000000000054902f RBX: 0000000000000001 RCX: ffffffff8b5d92a9 RDX: 0000000000000000 RSI: ffffffff8da28d25 RDI: ffffffff8bf075c0 RBP: ffffed1003a51b58 R08: 0000000000000001 R09: ffffed10170a6655 R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001 R13: ffff88801d28dac0 R14: ffffffff908248d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124b0d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560d4a6cea38 CR3: 000000004b204000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x38d/0x500 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148