rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=4594/1/0x4000000000000000 softirq=77525/77525 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=69057, q=71 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 17111 Comm: syz.0.2326 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:mark_lock+0xaa/0x190 kernel/locking/lockdep.c:4774 Code: 61 c8 8d e8 98 a1 e5 ff 90 0f 0b 90 90 90 31 c9 4c 89 fe 4c 89 f7 b8 01 00 00 00 85 69 60 74 10 5b 41 5c 41 5d 41 5e 41 5f 5d cc cc cc cc cc 49 89 fe 49 89 f7 e8 35 b1 ff ff 89 c1 31 c0 85 RSP: 0018:ffffc90000007aa8 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000005 RCX: ffffffff936c5330 RDX: 0000000000000000 RSI: ffff888028eb0bf8 RDI: ffff888028eb0000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff84d5225b R10: ffffc90000007ca0 R11: fffff52000000f96 R12: 0000000000000002 R13: 0000000000000002 R14: ffff888028eb0bf8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881259e7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd10098ff98 CR3: 0000000053110000 CR4: 00000000003526f0 Call Trace: mark_usage kernel/locking/lockdep.c:4639 [inline] __lock_acquire+0x65a/0xd20 kernel/locking/lockdep.c:5191 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 debug_object_activate+0xbb/0x420 lib/debugobjects.c:818 debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1081 __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0x656/0xc60 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:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:747 Code: c7 c7 e0 20 34 8e e8 5f cd 5d 03 eb cc 66 66 66 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 0f 1e fa 41 57 41 56 53 65 ff 05 10 1d 1d 11 e8 db 87 de 09 89 RSP: 0018:ffffc9001bd77348 EFLAGS: 00000202 RAX: ffffffff822f8c98 RBX: 1ffffd4000346ef9 RCX: 0000000000000000 RDX: ffff888028eb0000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff822f8c67 R10: dffffc0000000000 R11: fffff94000346ef9 R12: 0000000000000000 R13: ffffea0001a377c0 R14: ffffffff822f8c67 R15: ffffea0001a377d8 rcu_read_lock include/linux/rcupdate.h:842 [inline] page_table_check_clear+0x1c1/0x700 mm/page_table_check.c:77 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] get_and_clear_full_ptes include/linux/pgtable.h:725 [inline] zap_present_folio_ptes mm/memory.c:1627 [inline] zap_present_ptes mm/memory.c:1709 [inline] do_zap_pte_range mm/memory.c:1810 [inline] zap_pte_range mm/memory.c:1854 [inline] zap_pmd_range mm/memory.c:1946 [inline] zap_pud_range mm/memory.c:1975 [inline] zap_p4d_range mm/memory.c:1996 [inline] unmap_page_range+0x344b/0x4370 mm/memory.c:2017 unmap_single_vma mm/memory.c:2060 [inline] unmap_vmas+0x399/0x580 mm/memory.c:2104 exit_mmap+0x240/0xb40 mm/mmap.c:1280 __mmput+0x118/0x430 kernel/fork.c:1148 exit_mm+0x1da/0x2c0 kernel/exit.c:582 do_exit+0x648/0x2300 kernel/exit.c:954 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x72/0x130 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+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa34df8eec9 Code: Unable to access opcode bytes at 0x7fa34df8ee9f. RSP: 002b:00007fa34eed80e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 00007fa34e1e5fa8 RCX: 00007fa34df8eec9 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fa34e1e5fac RBP: 00007fa34e1e5fa0 R08: 7fffffffffffffff R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa34e1e6038 R14: 00007ffd2fd30ea0 R15: 00007ffd2fd30f88 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g69057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=46571 rcu: rcu_preempt kthread starved for 10502 jiffies! g69057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 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