rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=149441, q=823590 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 286 (4295024987-4295024701), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 287 jiffies! g149441 f0x2 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:28016 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0x164/0x360 kernel/sched/core.c:7322 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31337 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_unbound macvlan_process_broadcast RIP: 0010:memset_orig+0x15/0xb0 arch/x86/lib/memset_64.S:57 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 48 0f af c1 <41> 89 f9 41 83 e1 07 75 74 48 89 d1 48 c1 e9 06 74 39 66 0f 1f 84 RSP: 0018:ffffc90000006ac8 EFLAGS: 00000006 RAX: 0000000000000000 RBX: ffffffff8bcf6d20 RCX: 0000000000000000 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90000006ad8 RBP: ffff888053455300 R08: ffffc90000006ae7 R09: 1ffff92000000d5c R10: ffffc90000006ad8 R11: fffff52000000d5d R12: ffff888053455300 R13: dffffc0000000000 R14: ffff8880b86283e0 R15: ffff8880b86283d0 FS: 0000000000000000(0000) GS:ffff88812527c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555607384e8 CR3: 000000004221c000 CR4: 00000000003526f0 Call Trace: debug_object_deactivate+0x36/0x250 lib/debugobjects.c:918 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:2000 [inline] __hrtimer_run_queues+0x239/0xa10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215 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+0x52/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:unwind_next_frame+0x157/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: d8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 9b 1c 00 00 f6 03 03 0f 85 fa 19 00 00 49 8d 5e 35 48 89 d8 48 c1 e8 03 48 89 04 24 <42> 0f b6 04 20 84 c0 0f 85 92 1c 00 00 4c 89 7c 24 10 4c 89 6c 24 RSP: 0018:ffffc90000006e20 EFLAGS: 00000a03 RAX: 1ffff92000000ddf RBX: ffffc90000006efd RCX: 0000000080000102 RDX: 0000000000000000 RSI: ffffffff8c291100 RDI: ffffffff8c2910c0 RBP: 1ffff92000000de0 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90000006f18 R11: ffffffff81b10630 R12: dffffc0000000000 R13: ffffffff8176a21f R14: ffffc90000006ec8 R15: 1ffff92000000dd9 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4610 [inline] slab_alloc_node mm/slub.c:4939 [inline] kmem_cache_alloc_node_noprof+0x380/0x680 mm/slub.c:4991 __alloc_skb+0x1d7/0x7a0 net/core/skbuff.c:704 alloc_skb include/linux/skbuff.h:1386 [inline] synproxy_send_client_synack+0x175/0xde0 net/netfilter/nf_synproxy_core.c:463 nft_synproxy_eval_v4+0x37b/0x530 net/netfilter/nft_synproxy.c:60 nft_synproxy_do_eval+0x335/0x550 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1b10 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6206 [inline] __netif_receive_skb net/core/dev.c:6319 [inline] process_backlog+0xa34/0x1860 net/core/dev.c:6670 __napi_poll+0xaa/0x330 net/core/dev.c:7729 napi_poll net/core/dev.c:7792 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7949 handle_softirqs+0x225/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] netif_rx+0x83/0x90 net/core/dev.c:5779 macvlan_broadcast+0x375/0x630 drivers/net/macvlan.c:292 macvlan_multicast_rx drivers/net/macvlan.c:-1 [inline] macvlan_process_broadcast+0x437/0x660 drivers/net/macvlan.c:344 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478 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