rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=44401, q=1294 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 436 (4295005623-4295005187), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 437 jiffies! g44401 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1539/0x5080 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0x164/0x360 kernel/sched/core.c:7004 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:467 ret_from_fork+0x51b/0xa40 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: 10556 Comm: kworker/u8:1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: wg-kex-wg1 wg_packet_handshake_send_worker RIP: 0010:irqtime_account_irq+0x52/0x1c0 kernel/sched/cputime.c:63 Code: 00 00 fc ff df 4c 8d 3c dd 90 b7 19 8e 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 ff e8 25 66 93 00 83 3d 8e 8a 83 11 00 <0f> 84 40 01 00 00 48 c7 c3 c8 03 18 93 49 03 1f e8 39 05 06 0a 89 RSP: 0000:ffffc90000006db8 EFLAGS: 00000002 RAX: 1ffffffff1c336f2 RBX: 0000000000000000 RCX: 0000000080010101 RDX: 0000000000000000 RSI: ffffffff8c275260 RDI: ffffffff8c275220 RBP: 0000000000010000 R08: ffffffff90108ab7 R09: 1ffffffff2021156 R10: dffffc0000000000 R11: fffffbfff2021157 R12: dffffc0000000000 R13: 0000000000000000 R14: ffff888031e8dac0 R15: ffffffff8e19b790 FS: 0000000000000000(0000) GS:ffff8881252a4000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcd37800000 CR3: 000000002c976000 CR4: 00000000003526f0 Call Trace: instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x4a/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 01 bd ff 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 1b ad 76 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 40 9f 02 0a cc 48 8d 3d 38 cb 72 RSP: 0000:ffffc90000006eb8 EFLAGS: 00000286 RAX: 768ca6c441fd1f00 RBX: 0000000000000000 RCX: 0000000080000101 RDX: 000000007f45ee1d RSI: ffffffff8e1528a1 RDI: ffffffff8c275280 RBP: ffffffff81763295 R08: ffffffff81763295 R09: ffffffff8e7601a0 R10: ffffc90000007018 R11: ffffffff81b02be0 R12: 0000000000000002 R13: ffffffff8e7601a0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 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 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2667 [inline] slab_free mm/slub.c:6079 [inline] kmem_cache_free+0x180/0x610 mm/slub.c:6205 nft_synproxy_eval_v6+0x352/0x4e0 net/netfilter/nft_synproxy.c:92 nft_synproxy_do_eval+0x3ce/0x580 net/netfilter/nft_synproxy.c:146 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x45e/0x1990 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x29d/0x380 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6152 [inline] __netif_receive_skb net/core/dev.c:6265 [inline] process_backlog+0x7dd/0x1950 net/core/dev.c:6617 __napi_poll+0xae/0x340 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7896 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:626 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 blake2s_compress+0xf9/0x1eb0 lib/crypto/x86/blake2s.h:42 blake2s_update+0x14b/0x450 lib/crypto/blake2s.c:119 hmac+0x1fc/0x3b0 drivers/net/wireguard/noise.c:324 kdf+0x126/0x2b0 drivers/net/wireguard/noise.c:367 mix_dh drivers/net/wireguard/noise.c:413 [inline] wg_noise_handshake_create_initiation+0x2bc/0x830 drivers/net/wireguard/noise.c:550 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline] wg_packet_handshake_send_worker+0x18d/0x350 drivers/net/wireguard/send.c:51 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0xb46/0x1140 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245