rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (2 ticks this GP) idle=c6a4/1/0x4000000000000000 softirq=88100/88100 fqs=5 rcu: (detected by 0, t=10503 jiffies, g=69013, q=351 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 18572 Comm: syz.4.2359 Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:121 [inline] RIP: 0010:lock_release+0x69/0x3e0 kernel/locking/lockdep.c:5879 Code: 05 1c 83 df 0d 73 16 e8 c5 c8 08 00 84 c0 75 0d f6 05 11 81 c9 0d 01 0f 84 ad 02 00 00 83 3d dd b1 df 0d 00 0f 84 44 02 00 00 <65> 8b 05 c0 ef d3 10 85 c0 0f 85 35 02 00 00 65 4c 8b 3c 25 08 d0 RSP: 0018:ffffc90000a08c38 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000806 RCX: 744f8ce5ee916400 RDX: 0000000000010000 RSI: ffffffff8bc0fa40 RDI: ffffffff8bc0fa00 RBP: ffffc90000a08d30 R08: ffffffff8f7d9f77 R09: 1ffffffff1efb3ee R10: dffffc0000000000 R11: fffffbfff1efb3ef R12: dffffc0000000000 R13: ffffffff81ae2418 R14: ffff8880b89276d8 R15: 1ffff92000141194 FS: 00007f40c28776c0(0000) GS:ffff888126203000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1bcf8e5270 CR3: 000000007aa3a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x70/0x110 kernel/locking/spinlock.c:194 __run_hrtimer kernel/time/hrtimer.c:1757 [inline] __hrtimer_run_queues+0x408/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5870 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 cb c3 d3 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000c60f760 EFLAGS: 00000206 RAX: 744f8ce5ee916400 RBX: 0000000000000000 RCX: 744f8ce5ee916400 RDX: 0000000000000000 RSI: ffffffff8d91f838 RDI: ffffffff8bc0fa60 RBP: ffffffff82086dfa R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff82086dfa R12: 0000000000000002 R13: ffffffff8df3b860 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] do_fault_around mm/memory.c:5475 [inline] do_read_fault mm/memory.c:5509 [inline] do_fault mm/memory.c:5652 [inline] do_pte_missing mm/memory.c:4160 [inline] handle_pte_fault mm/memory.c:5997 [inline] __handle_mm_fault+0x2826/0x5380 mm/memory.c:6140 handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6309 faultin_page mm/gup.c:1193 [inline] __get_user_pages+0x16f0/0x2a40 mm/gup.c:1491 populate_vma_page_range+0x26b/0x340 mm/gup.c:1929 __mm_populate+0x24c/0x380 mm/gup.c:2032 mm_populate include/linux/mm.h:3487 [inline] vm_mmap_pgoff+0x3f0/0x4c0 mm/util.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f40c198e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f40c2877038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f40c1bb5fa0 RCX: 00007f40c198e969 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f40c1a10ab1 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f40c1bb5fa0 R15: 00007ffcedeec028 rcu: rcu_preempt kthread starved for 10480 jiffies! g69013 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:27304 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 18570 Comm: rm Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xe69/0x11c0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 10 6d 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 bb 68 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 a0 68 0b RSP: 0018:ffffc90003987700 EFLAGS: 00000293 RAX: ffffffff81b45540 RBX: ffff8880b883abc0 RCX: ffff88807d04da00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003987860 R08: ffffffff8f7d9f77 R09: 1ffffffff1efb3ee R10: dffffc0000000000 R11: fffffbfff1efb3ef R12: 1ffff11017127e69 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b893f348 FS: 0000000000000000(0000) GS:ffff888126103000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1bcf8e4440 CR3: 000000006de9e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1275 [inline] flush_tlb_mm_range+0x6ae/0x12b0 arch/x86/mm/tlb.c:1365 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline] tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:496 exit_mmap+0x474/0xba0 mm/mmap.c:1297 __mmput+0x118/0x410 kernel/fork.c:1379 exit_mm+0x1da/0x2c0 kernel/exit.c:589 do_exit+0x859/0x2550 kernel/exit.c:940 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111 x64_sys_call+0x21ba/0x21c0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1bcf9a2a90 Code: Unable to access opcode bytes at 0x7f1bcf9a2a66. RSP: 002b:00007ffe090234d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f1bcfa93860 RCX: 00007f1bcf9a2a90 RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00007f1bcfa93860 R08: 00007ffe09023350 R09: 00007ffe09023430 R10: 00007ffe09023390 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f1bcfa97658 R15: 0000000000000001