rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10574 jiffies, g=124345, q=3042 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 4642 (4295023981-4295019339), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 4644 jiffies! g124345 f0x2 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7376 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x480 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: 15304 Comm: kworker/R-bond1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Workqueue: 0x0 (bond12) RIP: 0010:__hrtimer_run_queues+0x11a/0xa10 kernel/time/hrtimer.c:2112 Code: 08 00 00 e8 98 9f 13 00 4c 89 74 24 58 49 c1 e6 07 48 8b 44 24 10 4a 8d 1c 30 48 83 c3 68 48 89 d8 48 c1 e8 03 42 80 3c 28 00 <74> 08 48 89 df e8 cc a3 83 00 89 6c 24 24 48 8b 44 24 10 4e 8d 3c RSP: 0018:ffffc90000a16f08 EFLAGS: 00000046 RAX: 1ffff110170e5075 RBX: ffff8880b87283a8 RCX: ffff888056308000 RDX: 8000000001000301 RSI: 0000000001000101 RDI: 0000000000000021 RBP: 0000000000000005 R08: 0000000001000101 R09: 0000000000000001 R10: dffffc0000000000 R11: fffff52000142de8 R12: ffff8880b8728280 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8728428 FS: 0000000000000000(0000) GS:ffff888124dca000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd3c995da08 CR3: 000000007f05a000 CR4: 00000000003526f0 Call Trace: hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2250 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:unwind_next_frame+0x16e/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: fa 19 00 00 49 8d 5e 35 48 89 d8 48 c1 e8 03 48 89 04 24 42 0f b6 04 20 84 c0 0f 85 92 1c 00 00 4c 89 7c 24 10 4c 89 6c 24 50 <0f> b6 1b 48 8b 44 24 20 42 80 3c 20 00 4d 8d 7e 48 74 08 4c 89 ff RSP: 0018:ffffc90000a17200 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc90000a172dd RCX: 8000000000000302 RDX: 00000000b26eefda RSI: ffffffff8c6dac60 RDI: ffffffff8c6dac20 RBP: 1ffff92000142e5c R08: ffffffff8177f1df R09: 0000000000000000 R10: ffffc90000a172f8 R11: ffffffff81b293f0 R12: dffffc0000000000 R13: ffffffff8177f1df R14: ffffc90000a172a8 R15: 1ffff92000142e55 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+0x40/0x50 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:2748 [inline] slab_free mm/slub.c:6508 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6635 skb_ext_reset include/linux/skbuff.h:5133 [inline] skb_scrub_packet+0x2c8/0x3d0 net/core/skbuff.c:6301 ____dev_forward_skb include/linux/netdevice.h:4483 [inline] __dev_forward_skb2+0x28c/0x730 net/core/dev.c:2466 veth_forward_skb drivers/net/veth.c:324 [inline] veth_xmit+0x493/0xe60 drivers/net/veth.c:380 __netdev_start_xmit include/linux/netdevice.h:5429 [inline] netdev_start_xmit include/linux/netdevice.h:5438 [inline] xmit_one net/core/dev.c:3937 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3953 __dev_queue_xmit+0x14c0/0x3820 net/core/dev.c:4926 dev_queue_xmit include/linux/netdevice.h:3461 [inline] br_dev_queue_push_xmit+0x370/0x4b0 net/bridge/br_forward.c:53 NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:325 br_nf_post_routing+0xa51/0xee0 net/bridge/br_netfilter_hooks.c:964 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:323 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66 br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:1165 [inline] br_nf_forward_finish+0xa76/0xea0 net/bridge/br_netfilter_hooks.c:667 NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:325 br_nf_forward_ip+0x7e7/0xa30 net/bridge/br_netfilter_hooks.c:721 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:323 __br_forward+0x397/0x540 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver net/bridge/br_forward.c:191 [inline] br_flood+0x3e3/0x8d0 net/bridge/br_forward.c:245 br_handle_frame_finish+0x1119/0x1950 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:325 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x1329/0x1600 net/bridge/br_input.c:451 __netif_receive_skb_core+0x989/0x30c0 net/core/dev.c:6152 __netif_receive_skb_one_core net/core/dev.c:6263 [inline] __netif_receive_skb net/core/dev.c:6378 [inline] process_backlog+0x727/0x18b0 net/core/dev.c:6729 __napi_poll+0xaa/0x330 net/core/dev.c:7798 napi_poll net/core/dev.c:7861 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8018 handle_softirqs+0x226/0x860 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775 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:finish_task_switch+0x413/0xc60 kernel/sched/core.c:5384 Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 17 0e 53 0a e8 92 1a 3a 00 fb 4c 8b 65 c8 <49> 8d bc 24 10 17 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 RSP: 0018:ffffc90007467a60 EFLAGS: 00000206 RAX: 000000000003806f RBX: ffff8880b873c8e0 RCX: 8000000000000001 RDX: 0000000000000000 RSI: ffffffff8e41591d RDI: ffffffff8c6dac80 RBP: ffffc90007467ab0 R08: ffffffff907a5f7f R09: 1ffffffff20f4bef R10: dffffc0000000000 R11: fffffbfff20f4bf0 R12: ffff888056308000 R13: ffff8880b873c8a8 R14: dffffc0000000000 R15: 1ffff110170e791c context_switch kernel/sched/core.c:5536 [inline] __schedule+0x17e3/0x58f0 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7376 rescuer_thread+0xf7f/0x10e0 kernel/workqueue.c:3752 kthread+0x38b/0x480 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: 7149 callbacks suppressed 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:d6:83:34:5f:c9:d2, 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:1c, vlan:0)