rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P24/1:b..l rcu: (detected by 1, t=10504 jiffies, g=54085, q=4797 ncpus=2) task:kworker/1:0 state:R running task stack:22144 pid:24 tgid:24 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: mld mld_ifc_work Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7413 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457 spin_unlock_bh include/linux/spinlock.h:396 [inline] rt6_uncached_list_add net/ipv6/route.c:146 [inline] icmp6_dst_alloc+0x39b/0x430 net/ipv6/route.c:3364 mld_sendpack+0x697/0xe10 net/ipv6/mcast.c:1858 mld_send_cr net/ipv6/mcast.c:2170 [inline] mld_ifc_work+0x842/0xd60 net/ipv6/mcast.c:2710 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 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: rcu_preempt kthread starved for 1937 jiffies! g54085 f0x0 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:27752 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 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: 5347 Comm: kworker/0:3 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: wg-crypt-wg1 wg_packet_tx_worker RIP: 0010:lock_acquire+0xf3/0x350 kernel/locking/lockdep.c:5868 Code: 83 1c 2e 0a 65 ff 05 ec 3d ca 11 45 31 c9 4c 89 7c 24 08 41 f7 c7 00 02 00 00 41 0f 94 c1 4c 89 ef 89 de 8b 54 24 04 44 89 e1 <45> 89 f0 6a 00 6a 00 6a 00 55 ff 74 24 30 e8 da 02 00 00 48 83 c4 RSP: 0018:ffffc90000006930 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880b86281d8 RBP: ffffffff81b3a3d6 R08: 0000000000000001 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff20ae8e7 R12: 0000000000000000 R13: ffff8880b86281d8 R14: 0000000000000001 R15: 0000000000000046 FS: 0000000000000000(0000) GS:ffff888124f55000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f64152f4582 CR3: 000000007f6aa000 CR4: 00000000003526f0 Call Trace: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:174 __run_hrtimer kernel/time/hrtimer.c:2036 [inline] __hrtimer_run_queues+0x466/0xa10 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:__orc_find arch/x86/kernel/unwind_orc.c:110 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:244 [inline] RIP: 0010:unwind_next_frame+0x2bb/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: d5 4c 39 e2 0f 86 22 02 00 00 49 29 d5 49 c1 fd 02 4a 8d 04 6d 00 00 00 00 4c 01 e8 48 8d 14 46 49 bc 00 00 00 00 00 fc ff df 8c 01 00 00 31 ed e9 e8 18 00 00 48 81 fd 00 e0 c8 91 0f 92 c0 RSP: 0018:ffffc90000006cc0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff90cf3c24 RCX: ffffffff90cf3c28 RDX: ffffffff917c6070 RSI: ffffffff917c6070 RDI: ffffffff8c4bbe20 RBP: ffffffff89ec1844 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c60 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffc90000006d68 R15: ffffffff90cf3c28 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:4584 [inline] slab_alloc_node mm/slub.c:4917 [inline] kmem_cache_alloc_noprof+0x2a0/0x5f0 mm/slub.c:4931 skb_ext_maybe_cow net/core/skbuff.c:7118 [inline] skb_ext_add+0x1b6/0x8e0 net/core/skbuff.c:7193 nf_bridge_unshare net/bridge/br_netfilter_hooks.c:170 [inline] br_nf_forward_ip+0xc3/0xa30 net/bridge/br_netfilter_hooks.c:686 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+0x23e/0x3f0 include/linux/netfilter.h:316 __br_forward+0x397/0x540 net/bridge/br_forward.c:115 br_handle_frame_finish+0x1175/0x1990 net/bridge/br_input.c:229 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:6099 __netif_receive_skb_one_core net/core/dev.c:6210 [inline] __netif_receive_skb net/core/dev.c:6325 [inline] process_backlog+0x706/0x1860 net/core/dev.c:6676 __napi_poll+0xaa/0x330 net/core/dev.c:7735 napi_poll net/core/dev.c:7798 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7955 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 wg_packet_create_data_done drivers/net/wireguard/send.c:247 [inline] wg_packet_tx_worker+0x16b/0x7e0 drivers/net/wireguard/send.c:276 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 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: 10246 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:2a:a0:a2:8b:08:39, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:2a:a0:a2:8b:08:39, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:1) net_ratelimit: 9169 callbacks suppressed bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:2a:a0:a2:8b:08:39, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:2a:a0:a2:8b:08:39, vlan:1) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:1)