rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=4d64/1/0x4000000000000000 softirq=114041/114041 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P24497/1:b..l rcu: (detected by 1, t=10502 jiffies, g=107661, q=458 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 26013 Comm: syz.4.9105 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x44/0x3e0 kernel/locking/lockdep.c:5879 Code: 8b 05 80 6d 26 11 48 89 44 24 28 0f 1f 44 00 00 65 8b 05 83 6d 26 11 83 f8 08 0f 83 9a 02 00 00 89 c0 48 0f a3 05 6c b9 26 0e <73> 16 e8 35 e9 08 00 84 c0 75 0d f6 05 05 a5 10 0e 01 0f 84 ad 02 RSP: 0018:ffffc90000007bf8 EFLAGS: 00000093 RAX: 0000000000000000 RBX: ffff88805b2182e8 RCX: 1ffff1100b643065 RDX: 0000000000010000 RSI: ffffffff89a289ef RDI: ffff88805b218300 RBP: ffff88805ac2e150 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f7c R12: ffff88805b218340 R13: ffffffff89a289ef R14: ffff88805b218300 R15: ffff88805ac2d800 FS: 0000000000000000(0000) GS:ffff8881259e1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001340 CR3: 000000000e138000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline] _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] advance_sched+0x99f/0xc90 net/sched/sch_taprio.c:986 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x52c/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:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 5b 7d 26 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90019fd74f0 EFLAGS: 00000206 RAX: 23e03971e2354700 RBX: 0000000000000000 RCX: 23e03971e2354700 RDX: 0000000000000000 RSI: ffffffff8ddb2001 RDI: ffffffff8c037e00 RBP: ffffffff822f8c47 R08: 0000000000000000 R09: ffffffff822f8c47 R10: dffffc0000000000 R11: fffff94000311a29 R12: 0000000000000002 R13: ffffffff8e33d660 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] page_table_check_clear+0x1a4/0x700 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 __do_sys_exit_group kernel/exit.c:1118 [inline] __se_sys_exit_group kernel/exit.c:1116 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1116 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f951ed8eba9 Code: Unable to access opcode bytes at 0x7f951ed8eb7f. RSP: 002b:00007ffcfb8b56e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f951ed8eba9 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffcfb8b574c R08: 00000004fb8b57df R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000761 R13: 00000000000927c0 R14: 00000000000bb86d R15: 00007ffcfb8b57a0 task:syz-executor state:R running task stack:21704 pid:24497 tgid:24497 ppid:24475 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7148 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7172 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+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1329 [inline] copy_pmd_range+0x7630/0x7f00 mm/memory.c:1389 copy_pud_range mm/memory.c:1426 [inline] copy_p4d_range mm/memory.c:1450 [inline] copy_page_range+0xc14/0x1270 mm/memory.c:1538 dup_mmap+0xf4f/0x1ab0 mm/mmap.c:1834 dup_mm kernel/fork.c:1504 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1556 copy_process+0x1706/0x3c00 kernel/fork.c:2196 kernel_clone+0x21e/0x840 kernel/fork.c:2624 __do_sys_clone kernel/fork.c:2765 [inline] __se_sys_clone kernel/fork.c:2749 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2749 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7603985413 RSP: 002b:00007ffe19469cf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7603985413 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555580c5a7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000000bb8e1 R15: 00007ffe19469e90 rcu: rcu_preempt kthread starved for 10495 jiffies! g107661 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:27288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 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 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 5875 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 e6 7f 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 91 7b 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 75 7b RSP: 0018:ffffc900045bf540 EFLAGS: 00000293 RAX: ffffffff81b45a1b RBX: 1ffff110170c8449 RCX: ffff88802d145ac0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900045bf6c0 R08: ffffffff8fc43c37 R09: 1ffffffff1f88786 R10: dffffc0000000000 R11: fffffbfff1f88787 R12: ffff8880b8642248 R13: dffffc0000000000 R14: ffff8880b873b240 R15: 0000000000000000 FS: 000055558aac0500(0000) GS:ffff888125ae1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f07d9b056c0 CR3: 0000000077778000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x6b1/0x12d0 arch/x86/mm/tlb.c:1451 dup_mmap+0x1598/0x1ab0 mm/mmap.c:1873 dup_mm kernel/fork.c:1504 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1556 copy_process+0x1706/0x3c00 kernel/fork.c:2196 kernel_clone+0x21e/0x840 kernel/fork.c:2624 __do_sys_clone kernel/fork.c:2765 [inline] __se_sys_clone kernel/fork.c:2749 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2749 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f07d8d85413 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffee4887568 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f07d8d85413 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055558aac07d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000000bb8ff R15: 00007ffee4887700 vkms_vblank_simulate: vblank timer overrun