rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=98ec/1/0x4000000000000000 softirq=129903/129905 fqs=0 rcu: (detected by 0, t=10506 jiffies, g=130073, q=226 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 24334 Comm: syz.7.6365 Not tainted 6.16.0-rc6-next-20250716-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:kasan_check_range+0xb/0x2c0 mm/kasan/generic.c:188 Code: ff 90 0f 0b cc 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 66 0f 1f 00 55 41 57 41 56 41 55 <41> 54 53 b0 01 48 85 f6 0f 84 ba 01 00 00 4c 8d 04 37 49 39 f8 0f RSP: 0018:ffffc90000a08ce0 EFLAGS: 00000046 RAX: ffffffff81adda1e RBX: ffff888027a4c340 RCX: ffffffff81adda37 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8fa2e130 RBP: 0000000000000000 R08: ffffffff99d16673 R09: 1ffffffff33a2cce R10: dffffc0000000000 R11: fffffbfff33a2ccf R12: dffffc0000000000 R13: 0000000000000001 R14: ffff8880b8727b80 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125ce2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c252a27 CR3: 000000000df38000 CR4: 00000000003526f0 Call Trace: instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] cpumask_test_cpu include/linux/cpumask.h:646 [inline] cpu_online include/linux/cpumask.h:1205 [inline] trace_hrtimer_start include/trace/events/timer.h:222 [inline] debug_activate kernel/time/hrtimer.c:485 [inline] enqueue_hrtimer+0x77/0x3a0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:_compound_head include/linux/page-flags.h:284 [inline] RIP: 0010:PageAnon include/linux/page-flags.h:735 [inline] RIP: 0010:page_table_check_clear+0x112/0x700 mm/page_table_check.c:75 Code: 03 c1 e5 18 bf 00 00 00 f5 89 ee e8 f8 01 90 ff 81 fd 00 00 00 f5 0f 84 5a 04 00 00 48 b8 00 00 00 00 00 fc ff df 80 3c 03 00 <74> 08 4c 89 ff e8 a4 c2 f4 ff 4d 8b 3f 4c 89 fe 48 83 e6 01 31 ff RSP: 0018:ffffc9000bf47590 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 1ffffd4000295f71 RCX: 0000000000000000 RDX: ffff888027f0bc00 RSI: 0000000000000000 RDI: 00000000f5000000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff822fc2aa R10: dffffc0000000000 R11: fffff94000295f71 R12: ffffea00014afbb0 R13: ffffea00014afb80 R14: 0000000000000001 R15: ffffea00014afb88 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:1505 [inline] zap_present_ptes mm/memory.c:1587 [inline] do_zap_pte_range mm/memory.c:1688 [inline] zap_pte_range mm/memory.c:1732 [inline] zap_pmd_range mm/memory.c:1824 [inline] zap_pud_range mm/memory.c:1853 [inline] zap_p4d_range mm/memory.c:1874 [inline] unmap_page_range+0x3445/0x4370 mm/memory.c:1895 unmap_single_vma mm/memory.c:1938 [inline] unmap_vmas+0x399/0x580 mm/memory.c:1982 exit_mmap+0x248/0xb50 mm/mmap.c:1280 __mmput+0x118/0x430 kernel/fork.c:1124 exit_mm+0x1da/0x2c0 kernel/exit.c:581 do_exit+0x648/0x2300 kernel/exit.c:947 do_group_exit+0x21c/0x2d0 kernel/exit.c:1100 __do_sys_exit_group kernel/exit.c:1111 [inline] __se_sys_exit_group kernel/exit.c:1109 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1109 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/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0cb598e929 Code: Unable to access opcode bytes at 0x7f0cb598e8ff. RSP: 002b:00007fffde6afc18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0cb598e929 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fffde6afc7c R08: 00000004de6afd0f R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000000e5 R13: 00000000000927c0 R14: 00000000000c07b9 R15: 00007fffde6afcd0 rcu: rcu_preempt kthread starved for 10506 jiffies! g130073 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:27432 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5314 [inline] __schedule+0x16fd/0x4cf0 kernel/sched/core.c:6697 __schedule_loop kernel/sched/core.c:6775 [inline] schedule+0x165/0x360 kernel/sched/core.c:6790 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2062 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2264 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 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: 24302 Comm: syz.6.6353 Not tainted 6.16.0-rc6-next-20250716-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:869 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 a6 6a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 51 66 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 35 66 RSP: 0018:ffffc9000bfc7480 EFLAGS: 00000293 RAX: ffffffff81b4409b RBX: 1ffff110170e7f61 RCX: ffff888057ae0000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000bfc7600 R08: ffffffff8fa2e137 R09: 1ffffffff1f45c26 R10: dffffc0000000000 R11: fffffbfff1f45c27 R12: ffff8880b873fb08 R13: dffffc0000000000 R14: ffff8880b863b1c0 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125be2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e61bff8 CR3: 0000000065a60000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1036 __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+0x6b1/0x12c0 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:490 [inline] tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497 exit_mmap+0x44c/0xb50 mm/mmap.c:1293 __mmput+0x118/0x430 kernel/fork.c:1124 exit_mm+0x1da/0x2c0 kernel/exit.c:581 do_exit+0x648/0x2300 kernel/exit.c:947 do_group_exit+0x21c/0x2d0 kernel/exit.c:1100 get_signal+0x1286/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:208 [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/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcc0538e929 Code: Unable to access opcode bytes at 0x7fcc0538e8ff. RSP: 002b:00007fcc0620d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fcc055b5fa8 RCX: 00007fcc0538e929 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fcc055b5fa8 RBP: 00007fcc055b5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcc055b5fac R13: 0000000000000000 R14: 00007fffdfc19a80 R15: 00007fffdfc19b68 ip6_tunnel: ip6gretap0: Local routing loop detected!