rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=946c/0/0x1 softirq=72196/72205 fqs=1 rcu: (detected by 0, t=10502 jiffies, g=93389, q=988 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:146 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:153 [inline] RIP: 0010:lock_is_held_type+0xf3/0x150 kernel/locking/lockdep.c:5984 Code: 0f 94 c3 eb 05 bb 01 00 00 00 48 c7 c7 d3 e6 6f 8e e8 f1 1a 00 00 b8 ff ff ff ff 65 0f c1 05 dc 2d b1 07 83 f8 01 75 25 9c 58 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 5b 41 5c RSP: 0018:ffffc90000a18d50 EFLAGS: 00000046 RAX: 0000000000000046 RBX: 0000000000000001 RCX: 8000000001000002 RDX: 8000000001000001 RSI: ffffffff8e6fe6d3 RDI: ffffffff8c6d8d80 RBP: 00000000ffffffff R08: 0000000001000001 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520001431a8 R12: 0000000000000046 R13: ffff88801e695dc0 R14: ffff8880b8728398 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005648b6db2078 CR3: 00000000781ea000 CR4: 00000000003526f0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] enqueue_hrtimer+0x79/0x2c0 kernel/time/hrtimer.c:1135 __run_hrtimer kernel/time/hrtimer.c:2084 [inline] __hrtimer_run_queues+0x4ce/0xa10 kernel/time/hrtimer.c:2125 hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2244 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 2c 91 02 c3 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 10 26 00 fb f4 cc 0a 03 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc900001a7e40 EFLAGS: 00000246 RAX: 0000000002109eed RBX: ffffffff819baa40 RCX: 8000000000000001 RDX: 0000000000000001 RSI: ffffffff8e477cab RDI: ffffffff8c6d8d80 RBP: ffffc900001a7f10 R08: ffff8880b8733b1b R09: 1ffff110170e6763 R10: dffffc0000000000 R11: ffffed10170e6764 R12: 0000000000000000 R13: 1ffff11003cd2bb8 R14: 1ffff92000034fd0 R15: dffffc0000000000 arch_safe_halt arch/x86/kernel/process.c:767 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:768 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x2e0/0x540 kernel/sched/idle.c:355 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x157 rcu: rcu_preempt kthread starved for 10478 jiffies! g93389 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5521 [inline] __schedule+0x1b57/0x5bc0 kernel/sched/core.c:7272 __schedule_loop kernel/sched/core.c:7349 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7364 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 0 UID: 0 PID: 12839 Comm: udevd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:csd_lock_wait kernel/smp.c:363 [inline] RIP: 0010:csd_lock kernel/smp.c:396 [inline] RIP: 0010:smp_call_function_many_cond+0x61e/0x1500 kernel/smp.c:944 Code: b6 04 04 84 c0 0f 85 d5 03 00 00 44 8b 3b 44 89 fe 83 e6 01 31 ff e8 51 51 0c 00 41 83 e7 01 75 07 e8 46 4c 0c 00 eb 3f f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 0f f7 03 01 RSP: 0018:ffffc900071af460 EFLAGS: 00000293 RAX: ffffffff81bb734e RBX: ffff8880b87415c8 RCX: ffff888028530000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900071af5b0 R08: ffff88802853159f R09: 1ffff110050a62b3 R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff110170e82b9 R13: 0000000000000001 R14: ffff8880b87415c0 R15: 0000000000000001 FS: 00007fe972c8c880(0000) GS:ffff888124cda000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055ccf452bbb0 CR3: 000000006ffd6000 CR4: 00000000003526f0 Call Trace: __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x8ff/0x1090 arch/x86/mm/tlb.c:1435 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline] tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:423 tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:549 unmap_region+0x2a5/0x330 mm/vma.c:535 vms_clear_ptes mm/vma.c:1383 [inline] vms_complete_munmap_vmas+0x427/0xbe0 mm/vma.c:1425 do_vmi_align_munmap+0x3b7/0x4b0 mm/vma.c:1684 do_vmi_munmap+0x252/0x2d0 mm/vma.c:1732 __vm_munmap+0x241/0x3e0 mm/vma.c:3390 __do_sys_munmap mm/mmap.c:1094 [inline] __se_sys_munmap mm/mmap.c:1091 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1091 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe97251e097 Code: 73 01 c3 48 8b 0d 61 2d 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 31 2d 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffeaee09788 EFLAGS: 00000206 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 000055ccf44fbbf0 RCX: 00007fe97251e097 RDX: 0000000000000000 RSI: 00000000009480e8 RDI: 00007fe971a00000 RBP: 000055ccf44fb910 R08: 000055ccf450e140 R09: 0000000000000006 R10: 0000000000000000 R11: 0000000000000206 R12: 000055ccb6b14588 R13: 00007ffeaee09810 R14: 0000000000000000 R15: 0000000000000000