rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=d46c/1/0x4000000000000000 softirq=74736/74737 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12463/3:b..l rcu: (detected by 0, t=10506 jiffies, g=68633, q=2009 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5738 Comm: kworker/1:6 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_power_efficient gc_worker RIP: 0010:_raw_spin_lock+0x0/0x40 kernel/locking/spinlock.c:157 Code: c0 48 89 ea 48 89 df 31 f6 5b 5d e9 ca be e9 f9 cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 53 48 89 fb bf 01 00 00 00 e8 1e b0 48 f6 ff 74 24 08 RSP: 0018:ffffc90000a08dd0 EFLAGS: 00000092 RAX: ffff8880567a32a8 RBX: ffff8880567a3300 RCX: ffff8880567a3280 RDX: 0000000000000000 RSI: ffffffff899a8b4e RDI: ffff8880567a32a8 RBP: ffff888076d4e000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff8880567a3300 R13: ffff88803485b0b8 R14: dffffc0000000000 R15: ffff8880b8528650 FS: 0000000000000000(0000) GS:ffff888124483000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbc5854da08 CR3: 000000005ab43000 CR4: 00000000003526f0 Call Trace: spin_lock include/linux/spinlock.h:342 [inline] advance_sched+0xe5/0xd20 net/sched/sch_taprio.c:930 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__seqprop_spinlock_sequence include/linux/seqlock.h:228 [inline] RIP: 0010:nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:343 [inline] RIP: 0010:gc_worker+0x2bb/0x1630 net/netfilter/nf_conntrack_core.c:1552 Code: 00 00 48 c7 c7 c8 c3 d7 90 e8 01 9d 36 f8 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 ff b7 5a f8 58 48 85 db 0f 85 97 0f 00 00 10 bd 5a f8 8b 1d 6a d0 29 07 89 dd 31 ff 83 e5 01 89 ee e8 ac RSP: 0018:ffffc9000434fb40 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff89adfde6 RDX: ffff88803485a540 RSI: ffffffff89adfdf5 RDI: ffff88803485a540 RBP: 0000000000002cb5 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000040000 R14: 000000000000165b R15: 0000000000001770 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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:28456 pid:12463 tgid:12463 ppid:5627 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] filemap_map_pages+0x15ac/0x2140 mm/filemap.c:3942 do_fault_around mm/memory.c:5867 [inline] do_read_fault mm/memory.c:5900 [inline] do_fault+0x985/0x1750 mm/memory.c:6043 do_pte_missing mm/memory.c:4566 [inline] handle_pte_fault mm/memory.c:6427 [inline] __handle_mm_fault+0x187d/0x2a00 mm/memory.c:6565 handle_mm_fault+0x37b/0xa30 mm/memory.c:6734 do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7fbc5764b180 RSP: 002b:00007ffe986743d8 EFLAGS: 00010202 RAX: 00007ffe986749f0 RBX: 00007ffe98674910 RCX: 0000000000000000 RDX: 00007ffe986749d0 RSI: 0000000000000025 RDI: 00007fbc57833c06 RBP: 00007ffe98674aec R08: 00007ffe98674b80 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000158 R13: 0000000000000000 R14: 00007fbc57833c06 R15: 00007ffe986749d0 rcu: rcu_preempt kthread starved for 10506 jiffies! g68633 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:27992 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 12197 Comm: udevd 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:get_current arch/x86/include/asm/current.h:23 [inline] RIP: 0010:write_comp_data+0x10/0x90 kernel/kcov.c:245 Code: 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 8b 05 d9 26 01 12 49 89 f8 49 89 f1 49 89 d2 <65> 48 8b 3d b0 26 01 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 RSP: 0018:ffffc9000306f5e8 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff81fc2c4d RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffff8880b8540f80 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a81f1 R14: 0000000000000001 R15: ffff8880b843c600 FS: 00007fbcece3d880(0000) GS:ffff888124383000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564d0ab88ff0 CR3: 00000000356e4000 CR4: 00000000003526f0 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0x5ad/0x1700 kernel/smp.c:892 on_each_cpu_cond_mask+0x40/0x90 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+0x45f/0x16f0 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_tlbonly include/asm-generic/tlb.h:499 [inline] tlb_flush_mmu mm/mmu_gather.c:423 [inline] tlb_finish_mmu+0x3fe/0x810 mm/mmu_gather.c:549 unmap_region+0x2d9/0x3b0 mm/vma.c:491 vms_clear_ptes mm/vma.c:1303 [inline] vms_complete_munmap_vmas+0xa4b/0xdd0 mm/vma.c:1345 do_vmi_align_munmap+0x44f/0x5f0 mm/vma.c:1604 do_vmi_munmap+0x1f8/0x3e0 mm/vma.c:1652 __vm_munmap+0x196/0x390 mm/vma.c:3285 __do_sys_munmap mm/mmap.c:1079 [inline] __se_sys_munmap mm/mmap.c:1076 [inline] __x64_sys_munmap+0x59/0x80 mm/mmap.c:1076 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbcec71e097 Code: 73 01 c3 48 8b 0d 61 2d 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 31 2d 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffd9cf09a68 EFLAGS: 00000206 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000564d0a95cf90 RCX: 00007fbcec71e097 RDX: 0000000000000000 RSI: 00000000009480e8 RDI: 00007fbceba00000 RBP: 0000564d0a95a2c0 R08: 0000564d0ab9a660 R09: 0000000000000006 R10: 0000000000000000 R11: 0000000000000206 R12: 0000564cfbb1a588 R13: 00007ffd9cf09af0 R14: 0000000000000000 R15: 0000000000000000