rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=4dcc/1/0x4000000000000000 softirq=81154/81162 fqs=2 rcu: (detected by 0, t=10506 jiffies, g=82629, q=152 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 14954 Comm: syz.8.2455 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:match_held_lock+0x7b/0xb0 kernel/locking/lockdep.c:5337 Code: c7 c2 70 03 e2 93 48 29 d0 48 c1 f8 03 48 ba 29 5c 8f c2 f5 28 5c 8f 48 0f af d0 bb 01 00 00 00 48 39 ca 74 02 31 db 89 d8 5b <41> 5e e9 b9 96 67 f5 cc 90 e8 97 f6 05 f9 85 c0 74 1c 83 3d 60 36 RSP: 0018:ffffc90000a08cc8 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff8880545949d8 RCX: 0000000080010003 RDX: ffff888054593d80 RSI: ffff88804bbbf2c0 RDI: ffff8880545949d8 RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000141190 R12: 0000000000000046 R13: ffff888054593d80 R14: ffff88804bbbf2c0 R15: 0000000000000005 FS: 00007ff1b108b6c0(0000) GS:ffff88812538d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3151aff8 CR3: 000000006afc7000 CR4: 0000000000350ef0 Call Trace: __lock_is_held kernel/locking/lockdep.c:5601 [inline] lock_is_held_type+0x89/0x150 kernel/locking/lockdep.c:5940 lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0x1c6/0xc20 net/sched/sch_taprio.c:935 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:trace_mod_memcg_lruvec_state include/trace/events/memcg.h:41 [inline] RIP: 0010:__mod_memcg_lruvec_state+0x1c1/0x360 mm/memcontrol.c:932 Code: 73 6a 89 c3 c1 e8 06 48 8d 3c c5 f0 ad 30 90 be 08 00 00 00 e8 30 68 f8 ff 48 0f a3 1d c8 18 f8 0d 73 09 e8 11 42 72 ff 84 c0 <74> 4d bf 01 00 00 00 e8 23 42 5b ff 65 8b 05 ec 9a 00 11 85 c0 74 RSP: 0018:ffffc900030cf488 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000080000003 RDX: 0000000000000000 RSI: ffffffff8c28adc0 RDI: ffffffff8c28ad80 RBP: 0000000000000001 R08: ffffffff9030adf7 R09: 1ffffffff20615be R10: dffffc0000000000 R11: fffffbfff20615bf R12: ffff888031ae1088 R13: 000000000000000f R14: 0000000000000001 R15: 0000607edaa1b2f0 mod_memcg_lruvec_state+0x1e7/0x270 mm/memcontrol.c:950 mod_lruvec_state mm/memcontrol.c:973 [inline] lruvec_stat_mod_folio+0x239/0x3e0 mm/memcontrol.c:993 __folio_mod_stat mm/rmap.c:1336 [inline] __folio_add_rmap mm/rmap.c:1428 [inline] __folio_add_file_rmap mm/rmap.c:1706 [inline] folio_add_file_rmap_ptes+0x689/0xc20 mm/rmap.c:1732 set_pte_range+0x52e/0x8a0 mm/memory.c:5619 finish_fault+0xe2f/0x1200 mm/memory.c:5757 do_read_fault mm/memory.c:5897 [inline] do_fault mm/memory.c:6027 [inline] do_pte_missing+0x20bb/0x33f0 mm/memory.c:4550 handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault mm/memory.c:6549 [inline] handle_mm_fault+0x1bd7/0x3170 mm/memory.c:6718 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x1683/0x2720 mm/gup.c:1428 populate_vma_page_range+0x2be/0x3c0 mm/gup.c:1860 __mm_populate+0x25f/0x390 mm/gup.c:1963 mm_populate include/linux/mm.h:4137 [inline] vm_mmap_pgoff+0x3aa/0x4f0 mm/util.c:586 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff1b019cdd9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff1b108b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007ff1b0415fa0 RCX: 00007ff1b019cdd9 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007ff1b0232d69 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff1b0416038 R14: 00007ff1b0415fa0 R15: 00007ffd7b3bf738 rcu: rcu_preempt kthread starved for 10495 jiffies! g82629 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 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: 9737 Comm: kworker/u8:17 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xfd4/0x13d0 kernel/smp.c:892 Code: 89 ee 83 e6 01 31 ff e8 da 07 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 85 03 0c 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 6a 03 0c 00 eb e5 44 89 RSP: 0018:ffffc9000687f700 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b863c148 RCX: ffff88802c131ec0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000687f840 R08: ffffffff9030adf7 R09: 1ffffffff20615be R10: dffffc0000000000 R11: fffffbfff20615bf R12: 1ffff110170e8169 R13: dffffc0000000000 R14: ffff8880b8740b48 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812528d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f24838f9286 CR3: 000000000e74a000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xab/0x290 mm/kfence/core.c:906 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 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