bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P29921/1:b..l rcu: (detected by 1, t=10502 jiffies, g=171637, q=1594 ncpus=2) task:syz.2.6370 state:R running task stack:25792 pid:29921 tgid:29920 ppid:18277 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 f1 1d 07 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 db a8 97 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 11 0a 0a cc 48 8d 3d 88 63 92 RSP: 0018:ffffc90005b071e0 EFLAGS: 00000282 RAX: d85036a5d922e900 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000970cbcf9 RSI: ffffffff8e21a1b7 RDI: ffffffff8c28af60 RBP: ffffffff81af618d R08: ffffffff81af618d R09: ffffffff8e95cda0 R10: ffffc90005b072f8 R11: ffffffff81b0efc0 R12: 0000000000000002 R13: ffffffff8e95cda0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] is_module_text_address+0x39/0x1e0 kernel/module/main.c:3921 kernel_text_address+0x94/0xe0 kernel/extable.c:119 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943 __slab_free+0x274/0x2c0 mm/slub.c:5612 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4950 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1383 [inline] sock_wmalloc+0xb2/0x130 net/core/sock.c:2831 pppoe_sendmsg+0x2b4/0x7c0 drivers/net/ppp/pppoe.c:798 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752 __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2841 __do_sys_sendmmsg net/socket.c:2868 [inline] __se_sys_sendmmsg net/socket.c:2865 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2865 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8c9f79ce59 RSP: 002b:00007f8ca0572028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f8c9fa15fa0 RCX: 00007f8c9f79ce59 RDX: 0000000000000484 RSI: 0000200000001340 RDI: 0000000000000003 RBP: 00007f8c9f832d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000024048084 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8c9fa16038 R14: 00007f8c9fa15fa0 R15: 00007ffce633b5a8 rcu: rcu_preempt kthread starved for 1938 jiffies! g171637 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:27536 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5827 Comm: kworker/0:7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_power_efficient neigh_periodic_work RIP: 0010:mark_lock+0x3/0x190 kernel/locking/lockdep.c:4714 Code: 3a 90 41 89 e9 48 89 df 48 8b 2c 24 e9 b6 fd ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 41 55 41 54 53 8b 46 20 89 c1 81 e1 00 00 03 00 83 f9 01 bb RSP: 0018:ffffc90000006780 EFLAGS: 00000006 RAX: 00000000000c6000 RBX: ffff88807c1568e0 RCX: ffffffff93e23370 RDX: 0000000000000008 RSI: ffff88807c1568c0 RDI: ffff88807c155c40 RBP: 0000000000000000 R08: ffffffff84bca163 R09: ffffffff9a686de8 R10: dffffc0000000000 R11: fffffbfff34f2e40 R12: 0000000000000002 R13: ffff88807c1568c0 R14: ffff88807c155c40 R15: 0000000000000006 FS: 0000000000000000(0000) GS:ffff88812528a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8c9d9b3ff8 CR3: 0000000079e06000 CR4: 00000000003526f0 Call Trace: mark_usage kernel/locking/lockdep.c:4674 [inline] __lock_acquire+0x6b5/0x2cf0 kernel/locking/lockdep.c:5191 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166 debug_object_activate+0x83/0x580 lib/debugobjects.c:835 debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline] debug_activate kernel/time/hrtimer.c:528 [inline] enqueue_hrtimer+0xa9/0x2c0 kernel/time/hrtimer.c:1109 __run_hrtimer kernel/time/hrtimer.c:1946 [inline] __hrtimer_run_queues+0x4d2/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 f1 1d 07 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 db a8 97 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 11 0a 0a cc 48 8d 3d 88 63 92 RSP: 0018:ffffc90000006d18 EFLAGS: 00000286 RAX: 3c09028aaa2dfd00 RBX: 0000000000000000 RCX: 0000000080000101 RDX: 00000000a42637f2 RSI: ffffffff8e21a1b7 RDI: ffffffff8c28af60 RBP: ffffffff8176f256 R08: ffffffff8176f256 R09: ffffffff8e95cda0 R10: ffffc90000006e78 R11: ffffffff81b0efc0 R12: 0000000000000002 R13: ffffffff8e95cda0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xc3/0x2550 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:2689 [inline] slab_free mm/slub.c:6250 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6377 skb_ext_reset include/linux/skbuff.h:5116 [inline] skb_release_head_state+0x270/0x360 net/core/skbuff.c:1181 skb_release_all net/core/skbuff.c:1187 [inline] __kfree_skb+0x24/0x210 net/core/skbuff.c:1203 kfree_skb_reason include/linux/skbuff.h:1322 [inline] kfree_skb include/linux/skbuff.h:1331 [inline] ip6_mc_input+0x8de/0xbd0 net/ipv6/ip6_input.c:638 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] netif_receive_skb_internal net/core/dev.c:6401 [inline] netif_receive_skb+0x278/0xbf0 net/core/dev.c:6460 NF_HOOK+0xa4/0x3a0 include/linux/netfilter.h:318 br_handle_frame_finish+0x1541/0x1c80 net/bridge/br_input.c:-1 nf_hook_bridge_pre net/bridge/br_input.c:313 [inline] br_handle_frame+0x80f/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x98f/0x3170 net/core/dev.c:6089 __netif_receive_skb_one_core net/core/dev.c:6200 [inline] __netif_receive_skb net/core/dev.c:6315 [inline] process_backlog+0x76d/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+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] neigh_periodic_work+0xc28/0xe50 net/core/neighbour.c:1038 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 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 net_ratelimit: 28440 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 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:4a:a3:fa:9c:43:af, 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: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 bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) net_ratelimit: 37191 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 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:4a:a3:fa:9c:43:af, 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: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 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:4a:a3:fa:9c:43:af, vlan:0)