rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16 rcu: (detected by 0, t=10502 jiffies, g=19365, q=11430 ncpus=2) task:ktimers/0 state:R running task stack:22056 pid:16 tgid:16 ppid:2 task_flags:0x4208040 flags:0x00080000 Call Trace: sched_show_task+0x4aa/0x5f0 kernel/sched/core.c:8184 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline] print_other_cpu_stall+0xf7b/0x1310 kernel/rcu/tree_stall.h:680 check_cpu_stall kernel/rcu/tree_stall.h:855 [inline] rcu_pending kernel/rcu/tree.c:3708 [inline] rcu_sched_clock_irq+0x93d/0x1050 kernel/rcu/tree.c:2744 update_process_times+0x234/0x2d0 kernel/time/timer.c:2475 tick_sched_handle kernel/time/tick-sched.c:296 [inline] tick_nohz_handler+0x38f/0x6b0 kernel/time/tick-sched.c:317 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x3a0/0xaf0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x44a/0x900 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+0xa1/0xc0 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 0d d2 5a f6 f7 c3 00 02 00 00 74 05 e8 80 c6 86 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 54 f1 4c f6 65 8b 05 ad ad 56 07 85 c0 74 18 5b 41 5e e9 51 3c RSP: 0018:ffffc90000157ba8 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000246 RCX: 0000000080000001 RDX: 0000000000000002 RSI: ffffffff8d885223 RDI: 0000000000000001 RBP: 1ffff110170c5102 R08: ffffffff8faf9737 R09: 1ffffffff1f5f2e6 R10: dffffc0000000000 R11: fffffbfff1f5f2e7 R12: ffffffff89548d40 R13: ffff8880b8628440 R14: ffff8880b8628440 R15: ffff888034afe440 __run_hrtimer kernel/time/hrtimer.c:2028 [inline] __hrtimer_run_queues+0x2ee/0xaf0 kernel/time/hrtimer.c:2096 hrtimer_run_softirq+0x18f/0x260 kernel/time/hrtimer.c:2113 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1151 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160 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 timer wakeup didn't happen for 10382 jiffies! g19365 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=12212 rcu: rcu_preempt kthread starved for 10383 jiffies! g19365 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27256 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x16dc/0x5500 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:arch_static_branch include/trace/events/preemptirq.h:40 [inline] RIP: 0010:trace_irq_enable+0x4/0x140 include/trace/events/preemptirq.h:40 Code: 05 6d 00 d1 10 00 00 00 00 c3 cc cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 41 56 <41> 54 53 66 90 65 8b 05 94 e8 cf 10 83 f8 08 73 37 89 c3 c1 e8 06 RSP: 0018:ffffc90000a4ec18 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000286 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff8b474260 RBP: 0000000000a12110 R08: ffffffff99d2a3eb R09: 1ffffffff33a547d R10: dffffc0000000000 R11: fffffbfff33a547e R12: 0000000000000000 R13: ffff888011678000 R14: ffffffff99d2a3e8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125d41000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f294de21ffe CR3: 000000002f3f4000 CR4: 00000000003526f0 Call Trace: trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:73 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline] _raw_spin_unlock_irqrestore+0x30/0x80 kernel/locking/spinlock.c:198 __debug_check_no_obj_freed lib/debugobjects.c:1180 [inline] debug_check_no_obj_freed+0x39e/0x450 lib/debugobjects.c:1201 slab_free_hook mm/slub.c:2608 [inline] slab_free mm/slub.c:6377 [inline] kmem_cache_free+0xfd/0x6c0 mm/slub.c:6504 kfree_skb_reason include/linux/skbuff.h:1323 [inline] kfree_skb include/linux/skbuff.h:1332 [inline] ip6_mc_input+0x909/0xbc0 net/ipv6/ip6_input.c:638 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:6212 [inline] __netif_receive_skb net/core/dev.c:6325 [inline] netif_receive_skb_internal net/core/dev.c:6411 [inline] netif_receive_skb+0x278/0xbf0 net/core/dev.c:6470 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+0x1282/0x1520 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+0x351/0xc50 net/core/dev.c:6676 __napi_poll+0xae/0x550 net/core/dev.c:7735 napi_poll net/core/dev.c:7798 [inline] net_rx_action+0x621/0xd70 net/core/dev.c:7955 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:622 run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160 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: 8533 callbacks suppressed bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) net_ratelimit: 7501 callbacks suppressed bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1 with own address as source address (addr:aa:aa:aa:aa:aa:18, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:19, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:19, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)