rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=103721, q=78925 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10453 (4295007671-4294997218), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10453 jiffies! g103721 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:26880 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 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+0x389/0x470 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 19413 Comm: kworker/R-bond5 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: bond5 bond_mii_monitor RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:write_comp_data kernel/kcov.c:245 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x8/0x90 kernel/kcov.c:314 Code: 89 44 11 20 c3 cc cc cc cc cc 0f 1f 84 00 00 00 00 00 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 15 f8 c6 73 11 65 8b 0d 19 c7 73 11 81 e1 00 01 ff 00 74 RSP: 0018:ffffc90000a078f0 EFLAGS: 00000246 RAX: ffffffff8a5a65ff RBX: ffff888075500400 RCX: dffffc0000000000 RDX: ffff888078979ec0 RSI: 0000000000000040 RDI: 0000000000000041 RBP: ffff888034ff2858 R08: ffffc90000a079cf R09: 0000000000000000 R10: ffffc90000a079c0 R11: fffff52000140f3a R12: 0000000000000000 R13: 0000000000000040 R14: 0000000000000080 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125387000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000101 CR3: 0000000036342000 CR4: 00000000003526f0 Call Trace: __ipv6_prefix_equal64_half include/net/ipv6.h:607 [inline] ipv6_prefix_equal include/net/ipv6.h:622 [inline] fib6_node_lookup_1+0x4bf/0x8a0 net/ipv6/ip6_fib.c:1655 fib6_node_lookup+0xe4/0x1d0 net/ipv6/ip6_fib.c:1703 fib6_table_lookup+0xbc/0xa80 net/ipv6/route.c:2247 ip6_pol_route+0x228/0x13d0 net/ipv6/route.c:2287 pol_lookup_func include/net/ip6_fib.h:667 [inline] __fib6_rule_action net/ipv6/fib6_rules.c:240 [inline] fib6_rule_action+0x265/0xc00 net/ipv6/fib6_rules.c:278 fib_rules_lookup+0x768/0xea0 net/core/fib_rules.c:339 fib6_rule_lookup+0x1a0/0x730 net/ipv6/fib6_rules.c:115 ip6_route_output_flags_noref net/ipv6/route.c:2703 [inline] ip6_route_output_flags+0x364/0x5d0 net/ipv6/route.c:2715 ip6_route_output include/net/ip6_route.h:100 [inline] __nf_ip6_route+0x42/0xd0 net/ipv6/netfilter.c:102 nf_ip6_route include/linux/netfilter_ipv6.h:57 [inline] synproxy_send_tcp_ipv6+0x275/0x6d0 net/netfilter/nf_synproxy_core.c:836 synproxy_send_client_synack_ipv6+0x814/0xcb0 net/netfilter/nf_synproxy_core.c:898 nft_synproxy_eval_v6+0x34a/0x4e0 net/netfilter/nft_synproxy.c:91 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+0x48d/0x1ae0 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 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:545 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6202 [inline] __netif_receive_skb net/core/dev.c:6315 [inline] process_backlog+0x7dd/0x1950 net/core/dev.c:6666 __napi_poll+0xae/0x340 net/core/dev.c:7733 napi_poll net/core/dev.c:7796 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7953 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 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_irq include/linux/spinlock_api_smp.h:188 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:206 Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 9a f5 f5 f5 48 89 df e8 a2 6a f6 f5 e8 cd 01 22 f6 fb bf 01 00 00 00 72 e9 e7 f5 65 8b 05 9b 9f 8d 07 85 c0 74 07 5b e9 01 48 00 00 RSP: 0018:ffffc9000588fa90 EFLAGS: 00000202 RAX: 000000000012b00b RBX: ffff88801aea3000 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8dface83 RDI: 0000000000000001 RBP: ffffc9000588fcb8 R08: ffffffff9030d4f7 R09: 1ffffffff2061a9e R10: dffffc0000000000 R11: fffffbfff2061a9f R12: 0000000002000000 R13: ffff88807c2f91a8 R14: dffffc0000000000 R15: ffff888026d4ed18 process_one_work kernel/workqueue.c:3283 [inline] process_scheduled_works+0x953/0x1860 kernel/workqueue.c:3397 rescuer_thread+0x827/0x1130 kernel/workqueue.c:3621 kthread+0x389/0x470 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