rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10506 jiffies, g=10601, q=964 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10506 (4294957279-4294946773), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10506 jiffies! g10601 f0x2 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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 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+0x4bc/0x870 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_power_efficient neigh_periodic_work RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:222 [inline] RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:233 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:646 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1205 [inline] RIP: 0010:trace_hrtimer_cancel include/trace/events/timer.h:317 [inline] RIP: 0010:debug_deactivate+0x5c/0x200 kernel/time/hrtimer.c:484 Code: 00 89 de e8 d6 2e 12 00 83 fb 07 77 6d e8 8c 2a 12 00 41 89 de c1 eb 06 48 8d 3c dd 70 dc 7c 8f be 08 00 00 00 e8 14 e2 77 00 <31> f6 4c 0f a3 35 4a 00 cf 0d 0f 92 c3 40 0f 92 c6 bf 02 00 00 00 RSP: 0018:ffffc90000a08d18 EFLAGS: 00000056 RAX: ffffffff81addc01 RBX: 0000000000000000 RCX: ffffffff81addc1c RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f7cdc70 RBP: ffffc90000a08e90 R08: ffffffff8f7cdc77 R09: 1ffffffff1ef9b8e R10: dffffc0000000000 R11: fffffbfff1ef9b8f R12: ffff8881436df340 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b8927bc0 FS: 0000000000000000(0000) GS:ffff88812623d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffb1c98b6e8 CR3: 000000001b6d8000 CR4: 00000000003526f0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1745 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:56 [inline] RIP: 0010:unwind_next_frame+0x1840/0x2390 arch/x86/kernel/unwind_orc.c:665 Code: 38 49 8d 7e 08 48 89 f8 48 c1 e8 03 80 3c 28 00 74 05 e8 13 17 b2 00 4d 8b 6e 08 4d 8d 7e 10 4c 89 f8 48 c1 e8 03 80 3c 28 00 <74> 08 4c 89 ff e8 f6 16 b2 00 49 8b 07 4d 39 e5 0f 96 c1 4c 39 e0 RSP: 0018:ffffc900001e72b8 EFLAGS: 00000246 RAX: 1ffff9200003ce73 RBX: ffffffff90099801 RCX: 0000000000000001 RDX: ffffc900001e73c8 RSI: dffffc0000000000 RDI: ffffc900001e7390 RBP: dffffc0000000000 R08: ffffc900001e7f38 R09: 0000000000000000 R10: ffffc900001e73d8 R11: fffff5200003ce7d R12: ffffc900001e7f48 R13: ffffc900001e0000 R14: ffffc900001e7388 R15: ffffc900001e7398 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2539 [inline] slab_free mm/slub.c:6630 [inline] kmem_cache_free+0x19b/0x690 mm/slub.c:6740 netlink_broadcast_filtered+0xec7/0x1000 net/netlink/af_netlink.c:1537 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2595 __neigh_notify+0x1ae/0x310 net/core/neighbour.c:3555 neigh_cleanup_and_release+0xb0/0x290 net/core/neighbour.c:120 neigh_periodic_work+0xb4f/0xe50 net/core/neighbour.c:1031 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245