rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=9dd4/1/0x4000000000000000 softirq=114276/114277 fqs=3 rcu: (detected by 1, t=10504 jiffies, g=109361, q=815 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 20676 Comm: syz.1.3855 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline] RIP: 0010:lock_acquire+0xc0/0x350 kernel/locking/lockdep.c:5864 Code: 97 11 85 c0 0f 85 bf 00 00 00 65 48 8b 05 20 11 97 11 83 b8 8c 0b 00 00 00 0f 85 aa 00 00 00 4c 89 74 24 10 4d 89 fe 9c 41 5f 48 c7 c7 13 ce fb 8d e8 53 32 06 0a 65 ff 05 9c 56 97 11 45 31 RSP: 0018:ffffc90000007ca0 EFLAGS: 00000046 RAX: ffff8880280e8000 RBX: 0000000000000000 RCX: 0000000000010003 RDX: 0000000000000001 RSI: ffffffff84bc57ba RDI: 1ffffffff1e22870 RBP: ffffffff84bc579a R08: 0000000000000001 R09: 0000000000000000 R10: dffffc0000000000 R11: fffff52000000fac R12: 0000000000000000 R13: ffffffff8f114380 R14: 0000000000000001 R15: 0000000000000046 FS: 0000555587cf7500(0000) GS:ffff888125295000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f69bb7b1d58 CR3: 0000000063812000 CR4: 0000000000350ef0 Call Trace: debug_objects_fill_pool lib/debugobjects.c:741 [inline] debug_object_activate+0x49a/0x580 lib/debugobjects.c:831 debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline] debug_activate kernel/time/hrtimer.c:528 [inline] enqueue_hrtimer+0xa9/0x2c0 kernel/time/hrtimer.c:1109 __run_hrtimer kernel/time/hrtimer.c:1946 [inline] __hrtimer_run_queues+0x4d2/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 1d e5 f7 f5 f7 c3 00 02 00 00 74 05 e8 f0 6f 23 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 64 67 e9 f5 65 8b 05 ed 50 8e 07 85 c0 74 18 5b 41 5e e9 bc e1 RSP: 0018:ffffc90003717678 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000202 RCX: 0000000080000001 RDX: 0000000000000006 RSI: ffffffff8dfa34f0 RDI: 0000000000000001 RBP: ffffc90003717728 R08: ffffffff903096f7 R09: 1ffffffff20612de R10: dffffc0000000000 R11: fffffbfff20612df R12: ffff88806d87f9d8 R13: ffffea0001b61fd0 R14: ffff88813fe349c0 R15: 0000000000000202 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] get_from_partial_node+0x47a/0x500 mm/slub.c:3835 get_from_partial mm/slub.c:3924 [inline] ___slab_alloc+0xb2/0x6c0 mm/slub.c:4440 __slab_alloc_node mm/slub.c:4510 [inline] slab_alloc_node mm/slub.c:4886 [inline] kmem_cache_alloc_noprof+0x12d/0x650 mm/slub.c:4905 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x156/0x580 lib/debugobjects.c:420 debug_objects_fill_pool lib/debugobjects.c:742 [inline] debug_object_assert_init+0x367/0x3b0 lib/debugobjects.c:1020 debug_hrtimer_assert_init kernel/time/hrtimer.c:495 [inline] hrtimer_start_range_ns+0x3f/0xed0 kernel/time/hrtimer.c:1477 futex_do_wait kernel/futex/waitwake.c:345 [inline] __futex_wait+0x197/0x420 kernel/futex/waitwake.c:691 futex_wait+0x121/0x390 kernel/futex/waitwake.c:719 do_futex+0x333/0x420 kernel/futex/syscalls.c:130 __do_sys_futex kernel/futex/syscalls.c:207 [inline] __se_sys_futex+0x3a8/0x450 kernel/futex/syscalls.c:188 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f69ba99cdd9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc54cfe008 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00000000001acc15 RCX: 00007f69ba99cdd9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f69bac1609c RBP: 0000000000000032 R08: 3fffffffffffffff R09: 0000000000000000 R10: 00007ffc54cfe110 R11: 0000000000000246 R12: 00007ffc54cfe130 R13: 00007f69bac1609c R14: 00000000001acc47 R15: 00007ffc54cfe110 rcu: rcu_preempt kthread starved for 10475 jiffies! g109361 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:26784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 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: 1 UID: 0 PID: 20673 Comm: syz.8.3854 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216 Code: 8b 3d 64 8c 60 0c 48 89 de 5b e9 33 ea 5f 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 48 0c 73 11 65 8b 15 69 0c 73 11 81 e2 00 01 ff 00 74 RSP: 0018:ffffc90002e67578 EFLAGS: 00000202 RAX: ffffffff81b9ab26 RBX: ffff8880b873c148 RCX: ffff88802d303d80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002e676c0 R08: ffffffff903096f7 R09: 1ffffffff20612de R10: dffffc0000000000 R11: fffffbfff20612df R12: 1ffff110170c8589 R13: dffffc0000000000 R14: ffff8880b8642c48 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125395000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1f657ec4b8 CR3: 00000000828e5000 CR4: 0000000000350ef0 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xfe6/0x13d0 kernel/smp.c:892 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __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+0x5c3/0x10b0 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:509 [inline] tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:423 tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:549 exit_mmap+0x498/0x9e0 mm/mmap.c:1313 __mmput+0x118/0x430 kernel/fork.c:1178 exit_mm+0x18e/0x250 kernel/exit.c:581 do_exit+0x6a2/0x22c0 kernel/exit.c:963 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117 get_signal+0x1284/0x1330 kernel/signal.c:3037 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f323a79cdd9 Code: Unable to access opcode bytes at 0x7f323a79cdaf. RSP: 002b:00007f323b6450e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f323aa16098 RCX: 00007f323a79cdd9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f323aa16098 RBP: 00007f323aa16090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f323aa16128 R14: 00007ffdb6b69850 R15: 00007ffdb6b69938