rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P38/1:b..l rcu: (detected by 0, t=10502 jiffies, g=219741, q=620 ncpus=2) task:khugepaged state:R running task stack:27216 pid:38 tgid:38 ppid:2 task_flags:0x200040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7552 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:kasan_check_range+0xd/0x2c0 mm/kasan/generic.c:199 Code: 8e e8 17 d8 f6 fe 90 0f 0b cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 55 41 57 41 56 41 55 41 54 <53> b0 01 48 85 f6 0f 84 ae 01 00 00 4c 8d 04 37 49 39 f8 0f 82 36 RSP: 0018:ffffc90000ae73d8 EFLAGS: 00000246 RAX: ffffffff823cc4b4 RBX: ffff88801c8928ac RCX: ffffffff823cc4cd RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88801c8928ac RBP: 0000000000000000 R08: ffff88801c8928ab R09: 1ffff11003912515 R10: dffffc0000000000 R11: ffffed1003912516 R12: 000000000000014e R13: 0000000000039c01 R14: dffffc0000000000 R15: ffff88801c892860 instrument_atomic_read include/linux/instrumented.h:82 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] __page_table_check_zero+0x1fd/0x3e0 mm/page_table_check.c:143 page_table_check_alloc include/linux/page_table_check.h:38 [inline] post_alloc_hook+0x23c/0x280 mm/page_alloc.c:1854 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x24ae/0x2530 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221 __alloc_pages_noprof+0x10/0x100 mm/page_alloc.c:5255 __folio_alloc_noprof+0x18/0x120 mm/page_alloc.c:5265 alloc_charge_folio+0x404/0x890 mm/khugepaged.c:1076 collapse_huge_page mm/khugepaged.c:1119 [inline] collapse_scan_pmd mm/khugepaged.c:1425 [inline] collapse_single_pmd+0x1b35/0x4480 mm/khugepaged.c:2437 collapse_scan_mm_slot mm/khugepaged.c:2552 [inline] khugepaged_do_scan mm/khugepaged.c:2632 [inline] khugepaged+0xa6c/0x18e0 mm/khugepaged.c:2687 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 starved for 10498 jiffies! g219741 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:28040 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0x164/0x360 kernel/sched/core.c:7322 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 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: 9777 Comm: syz.6.9430 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x10b5/0x14b0 kernel/smp.c:892 Code: 1e 89 de 83 e6 01 31 ff e8 98 02 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 44 fe 0b 00 eb 37 f3 90 41 0f b6 04 1c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 29 fe 0b 00 eb e5 44 89 RSP: 0018:ffffc90006f1f5a0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888051290000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90006f1f6c8 R08: ffffffff9030ecf7 R09: 1ffffffff2061d9e R10: dffffc0000000000 R11: fffffbfff2061d9f R12: 1ffff110170e8199 R13: ffff8880b863c2c8 R14: ffff8880b8740cc8 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812528f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff3b3f456b8 CR3: 0000000033a72000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x5c4/0x1090 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline] tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:423 tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:549 exit_mmap+0x4b2/0x9f0 mm/mmap.c:1313 __mmput+0x118/0x420 kernel/fork.c:1181 exit_mm+0x221/0x2d0 kernel/exit.c:610 do_exit+0x6cd/0x2360 kernel/exit.c:992 do_group_exit+0x22d/0x2f0 kernel/exit.c:1147 get_signal+0x121b/0x12c0 kernel/signal.c:3038 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd42a99ce59 Code: Unable to access opcode bytes at 0x7fd42a99ce2f. RSP: 002b:00007fd42b8daf38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: 0000000000000001 RBX: 0000200000000780 RCX: 00007fd42a99ce59 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000006 RBP: 00000000000004fa R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000500 R13: 0000200000000508 R14: 0000000000000e26 R15: 0000000000000000