rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=c78c/1/0x4000000000000000 softirq=131796/131797 fqs=0 rcu: (detected by 0, t=10502 jiffies, g=110969, q=207 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 23670 Comm: syz.7.3971 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x10/0x18 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 52 b8 01 00 00 00 31 d2 f0 0f b0 17 <75> 06 5a c3 cc cc cc cc 56 0f b6 f0 e8 9f ff ff ff 5e 5a c3 cc cc RSP: 0000:ffffc90000a08b98 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffffffff99f164d0 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff99f164d0 RBP: 1ffffffff33e2c9b R08: ffffffff99f164d3 R09: 1ffffffff33e2c9a R10: dffffc0000000000 R11: fffffbfff33e2c9b R12: dffffc0000000000 R13: 1ffffffff33e2c9c R14: ffffffff99f164e0 R15: ffffffff99f164d8 FS: 00007fd9413996c0(0000) GS:ffff888125aff000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe19db72020 CR3: 0000000093a48000 CR4: 00000000003526f0 Call Trace: pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:562 [inline] queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline] do_raw_spin_unlock+0x122/0x240 kernel/locking/spinlock_debug.c:142 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock_irqrestore+0x78/0x110 kernel/locking/spinlock.c:194 debug_object_activate+0x2e2/0x420 lib/debugobjects.c:836 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x30/0x3a0 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:697 RIP: 0010:trace_sched_exit_tp+0x45/0x110 include/trace/events/sched.h:886 Code: c4 8f be 08 00 00 00 e8 99 34 92 00 48 0f a3 1d b1 fc 31 0e 73 12 e8 5a 3f 15 00 84 c0 75 09 80 3d d5 de 1b 0e 00 74 0e 5b 5d 06 7f ef 09 cc 90 0f 0b 90 eb bf c6 05 be de 1b 0e 01 90 48 c7 RSP: 0000:ffffc9000cc7f598 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff888026dd9e00 RCX: 59c7fe6b38070800 RDX: 0000000000000000 RSI: ffffffff8c035860 RDI: ffffffff8c035820 RBP: ffffc9000cc7f7b8 R08: ffffffff8fc40337 R09: 1ffffffff1f88066 R10: dffffc0000000000 R11: fffffbfff1f88067 R12: dffffc0000000000 R13: 1ffff110170e7557 R14: ffff88801c723c00 R15: ffff888026ddb38c __schedule+0x17ae/0x4cc0 kernel/sched/core.c:6971 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common kernel/sched/completion.c:121 [inline] wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153 rdmsr_safe_on_cpu+0x150/0x230 arch/x86/lib/msr-smp.c:181 msr_read+0x14d/0x250 arch/x86/kernel/msr.c:66 vfs_read+0x1fd/0xa30 fs/read_write.c:570 ksys_read+0x145/0x250 fs/read_write.c:715 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: 0033:0x7fd94058ebe9 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:00007fd941399038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fd9407b6090 RCX: 00007fd94058ebe9 RDX: 0000000000018ff8 RSI: 0000200000019680 RDI: 0000000000000005 RBP: 00007fd940611e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd9407b6128 R14: 00007fd9407b6090 R15: 00007fff89ee01a8 rcu: rcu_preempt kthread starved for 10502 jiffies! g110969 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:27096 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 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+0x47c/0x820 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: 23708 Comm: syz.9.3982 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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 5c 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 91 58 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 58 RSP: 0018:ffffc9000cc57560 EFLAGS: 00000293 RAX: ffffffff81b5365b RBX: 1ffff110170e7f61 RCX: ffff88802ce03c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000cc576e0 R08: ffffffff8fc40337 R09: 1ffffffff1f88066 R10: dffffc0000000000 R11: fffffbfff1f88067 R12: ffff8880b873fb08 R13: dffffc0000000000 R14: ffff8880b863b1c0 R15: 0000000000000001 FS: 00007f9834d596c0(0000) GS:ffff8881259ff000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9829c1f000 CR3: 000000009180a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000004144 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 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 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 vms_clear_ptes+0x42c/0x540 mm/vma.c:1235 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277 do_vmi_align_munmap+0x358/0x420 mm/vma.c:1536 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584 __vm_munmap+0x23b/0x3d0 mm/vma.c:3155 __do_sys_munmap mm/mmap.c:1080 [inline] __se_sys_munmap mm/mmap.c:1077 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1077 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: 0033:0x7f9833f8ec77 Code: 00 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 0b 00 00 00 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:00007f9834d58e18 EFLAGS: 00000246 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f9833f8ec77 RDX: 0000000000000000 RSI: 0000000008400000 RDI: 00007f9829c00000 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000014f7 R10: 0000200000000982 R11: 0000000000000246 R12: 0000000000000007 R13: 00007f9834d58ef0 R14: 00007f9834d58eb0 R15: 00007f9829c00000