rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5178/1:b..l rcu: (detected by 0, t=10503 jiffies, g=13949, q=327 ncpus=2) task:klogd state:R running task stack:25568 pid:5178 tgid:5178 ppid:1 task_flags:0x400100 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7047 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:194 sock_def_readable+0x15b/0x5d0 net/core/sock.c:3611 unix_dgram_sendmsg+0xcbd/0x1830 net/unix/af_unix.c:2286 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] __sys_sendto+0x4a3/0x520 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3b49ae1407 RSP: 002b:00007ffe89fc2ba0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f3b49991c80 RCX: 00007f3b49ae1407 RDX: 000000000000007f RSI: 00007ffe89fc2ce0 RDI: 0000000000000003 RBP: 00007ffe89fc3110 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffe89fc3128 R13: 00007ffe89fc2ce0 R14: 0000000000000064 R15: 00007ffe89fc2ce0 rcu: rcu_preempt kthread starved for 10515 jiffies! g13949 f0x0 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:28064 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:rt6_score_route+0x71/0xa70 net/ipv6/route.c:753 Code: 80 3c 02 00 0f 85 65 07 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 75 00 49 8d be e0 00 00 00 48 89 fa 48 c1 ea 03 0f b6 04 02 <84> c0 74 08 3c 03 0f 8e 2f 07 00 00 45 8b b6 e0 00 00 00 44 89 e6 RSP: 0018:ffffc90000a07860 EFLAGS: 00000a02 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff8a209d18 RDX: 1ffff1100f34d41c RSI: ffffffff8a209d26 RDI: ffff888079a6a0e0 RBP: ffff888068ee28c8 R08: 0000000000000005 R09: 0000000000000000 R10: 000000000000000d R11: ffff88801dab2ff0 R12: 000000000000000d R13: 0000000000000003 R14: ffff888079a6a000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249f6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efda6f733e0 CR3: 0000000042683000 CR4: 00000000003526f0 Call Trace: find_match+0x222/0x15d0 net/ipv6/route.c:785 __find_rr_leaf+0x140/0xe00 net/ipv6/route.c:868 find_rr_leaf net/ipv6/route.c:889 [inline] rt6_select net/ipv6/route.c:933 [inline] fib6_table_lookup+0x57c/0xa30 net/ipv6/route.c:2233 ip6_pol_route+0x1cc/0x1230 net/ipv6/route.c:2269 pol_lookup_func include/net/ip6_fib.h:617 [inline] fib6_rule_lookup+0x536/0x720 net/ipv6/fib6_rules.c:120 ip6_route_input_lookup net/ipv6/route.c:2338 [inline] ip6_route_input+0x662/0xc70 net/ipv6/route.c:2641 ip6_rcv_finish_core.constprop.0+0x1a0/0x5d0 net/ipv6/ip6_input.c:66 ip6_rcv_finish+0x130/0x580 net/ipv6/ip6_input.c:77 ip_sabotage_in+0x21e/0x290 net/bridge/br_netfilter_hooks.c:990 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbe/0x200 net/netfilter/core.c:623 nf_hook.constprop.0+0x424/0x750 include/linux/netfilter.h:273 NF_HOOK include/linux/netfilter.h:316 [inline] ipv6_rcv+0xa4/0x650 net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6137 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6250 netif_receive_skb_internal net/core/dev.c:6336 [inline] netif_receive_skb+0x137/0x760 net/core/dev.c:6395 NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70 br_handle_frame_finish+0x10e8/0x1f00 net/bridge/br_input.c:235 br_nf_hook_thresh+0x307/0x410 net/bridge/br_netfilter_hooks.c:1167 br_nf_pre_routing_finish_ipv6+0x76a/0xfc0 net/bridge/br_netfilter_ipv6.c:154 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x3cd/0x8c0 net/bridge/br_netfilter_ipv6.c:184 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0xb28/0x14e0 net/bridge/br_input.c:442 __netif_receive_skb_core.constprop.0+0x6b3/0x35b0 net/core/dev.c:6024 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6135 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6250 process_backlog+0x4a2/0x1650 net/core/dev.c:6602 __napi_poll.constprop.0+0xb3/0x540 net/core/dev.c:7666 napi_poll net/core/dev.c:7729 [inline] net_rx_action+0x9f9/0xfa0 net/core/dev.c:7881 handle_softirqs+0x219/0x950 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 59 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6 RAX: 0000000001e52707 RBX: 0000000000000001 RCX: ffffffff8b7806d9 RDX: 0000000000000000 RSI: ffffffff8dacdb69 RDI: ffffffff8bf2b380 RBP: ffffed1003b56498 R08: 0000000000000001 R09: ffffed10170a673d R10: ffff8880b85339eb R11: ffff88801dab2ff0 R12: 0000000000000001 R13: ffff88801dab24c0 R14: ffffffff9088afd0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148 net_ratelimit: 9892 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:b2:85:ac:2d:5f:9b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:b2:85:ac:2d:5f:9b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:b2:85:ac:2d:5f:9b, vlan:0) net_ratelimit: 9077 callbacks suppressed bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:b2:85:ac:2d:5f:9b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:b2:85:ac:2d:5f:9b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:b2:85:ac:2d:5f:9b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)