rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=337281, q=465146 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 6201 (4295124811-4295118610), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 6202 jiffies! g337281 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:28056 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 25972 Comm: kworker/R-bond7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: 0x0 (bond7) RIP: 0010:__find_rr_leaf+0x317/0x740 net/ipv6/route.c:838 Code: 0f 85 84 02 00 00 48 8b 44 24 18 88 18 eb 1b e8 3f 9b 6f f7 eb 05 e8 38 9b 6f f7 49 bd 00 00 00 00 00 fc ff df 4c 8b 7c 24 38 <49> 83 c6 08 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 RSP: 0018:ffffc90000a07920 EFLAGS: 00000246 RAX: ffffffff8a565ae1 RBX: 0000000000000001 RCX: ffff8880496c8000 RDX: 0000000000000100 RSI: 00000000fffffffd RDI: 00000000fffffffd RBP: ffffc90000a07a78 R08: ffffc90000a07ba0 R09: ffffc90000a07bb0 R10: ffffc90000a07a00 R11: fffff52000140f42 R12: 1ffff11009ee3f8c R13: dffffc0000000000 R14: ffff88804f71fc00 R15: ffffc90000a07b78 FS: 0000000000000000(0000) GS:ffff88812537b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb53a01d9b8 CR3: 0000000036b0c000 CR4: 00000000003526f0 Call Trace: find_rr_leaf net/ipv6/route.c:893 [inline] rt6_select net/ipv6/route.c:937 [inline] fib6_table_lookup+0x3c6/0xae0 net/ipv6/route.c:2255 ip6_pol_route+0x229/0x14d0 net/ipv6/route.c:2292 pol_lookup_func include/net/ip6_fib.h:669 [inline] fib6_rule_lookup+0x556/0x730 net/ipv6/fib6_rules.c:123 ip6_route_input_lookup net/ipv6/route.c:2363 [inline] ip6_route_input+0x78d/0xb20 net/ipv6/route.c:2666 ip6_rcv_finish+0x141/0x280 net/ipv6/ip6_input.c:117 ip_sabotage_in+0x1e1/0x270 net/bridge/br_netfilter_hooks.c:988 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 __netif_receive_skb_one_core net/core/dev.c:6206 [inline] __netif_receive_skb net/core/dev.c:6319 [inline] netif_receive_skb_internal net/core/dev.c:6405 [inline] netif_receive_skb+0x278/0xbf0 net/core/dev.c:6464 NF_HOOK+0xa4/0x3a0 include/linux/netfilter.h:318 br_handle_frame_finish+0x1192/0x1990 net/bridge/br_input.c:-1 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6093 __netif_receive_skb_one_core net/core/dev.c:6204 [inline] __netif_receive_skb net/core/dev.c:6319 [inline] process_backlog+0x706/0x1860 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 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:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 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 9d ca f7 f5 f7 c3 00 02 00 00 74 05 e8 10 87 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 e4 e1 e8 f5 65 8b 05 2d b4 8f 07 85 c0 74 18 5b 41 5e e9 91 48 RSP: 0018:ffffc90004fd7988 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000a07 RCX: 0000000080000002 RDX: 0000000000000000 RSI: ffffffff8c291100 RDI: 0000000000000001 RBP: ffffc90004fd7bb0 R08: ffffffff903116f7 R09: 1ffffffff20622de R10: dffffc0000000000 R11: fffffbfff20622df R12: ffff8880496c8a78 R13: 1ffff920009faf3c R14: ffff8880496c8a78 R15: 1ffff110170e77cc task_rq_unlock kernel/sched/sched.h:1959 [inline] __set_cpus_allowed_ptr_locked+0x6ac/0x19c0 kernel/sched/core.c:3183 __set_cpus_allowed_ptr kernel/sched/core.c:3212 [inline] set_cpus_allowed_ptr+0x18f/0x1f0 kernel/sched/core.c:3222 worker_attach_to_pool+0x1da/0x390 kernel/workqueue.c:2744 rescuer_thread+0x335/0x10b0 kernel/workqueue.c:3614 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 net_ratelimit: 4704 callbacks suppressed bridge0: received packet on veth1_to_bridge with own address as source address (addr:22:6c:80:a9:fa:9b, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:22:6c:80:a9:fa:9b, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:22:6c:80:a9:fa:9b, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) net_ratelimit: 5730 callbacks suppressed bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:22:6c:80:a9:fa:9b, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:22:6c:80:a9:fa:9b, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)