rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=4be4/1/0x4000000000000000 softirq=18145/18145 fqs=0
rcu: 	(detected by 0, t=10502 jiffies, g=11409, q=347 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3536 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:__rb_change_child include/linux/rbtree_augmented.h:204 [inline]
RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:242 [inline]
RIP: 0010:rb_erase+0x3f1/0xe60 lib/rbtree.c:443
Code: 03 80 3c 28 00 74 08 4c 89 e7 e8 3a 2e ae f6 4d 8b 2c 24 41 83 e5 01 49 f7 dd 4d 21 fd eb 75 48 89 d8 48 c1 e8 03 80 3c 28 00 <0f> 84 a5 05 00 00 48 89 df e8 01 2f ae f6 e9 98 05 00 00 48 b8 00
RSP: 0018:ffffc90000a07be8 EFLAGS: 00000046
RAX: 1ffff110170e4f7a RBX: ffff8880b8727bd0 RCX: dffffc0000000000
RDX: 0000000000010100 RSI: ffff8880b8727bd0 RDI: ffff888020f8b348
RBP: dffffc0000000000 R08: ffffffff8fa37e37 R09: 1ffffffff1f46fc6
R10: dffffc0000000000 R11: fffffbfff1f46fc7 R12: ffff888020f8b340
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000600 CR3: 0000000027a10000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rb_erase_cached include/linux/rbtree.h:126 [inline]
 timerqueue_del+0xae/0x100 lib/timerqueue.c:57
 __remove_hrtimer kernel/time/hrtimer.c:1121 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1741 [inline]
 __hrtimer_run_queues+0x364/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 4b f3 02 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90000a07ff8 EFLAGS: 00000206
RAX: 56d4cf74bea5dc00 RBX: 0000000000000000 RCX: 56d4cf74bea5dc00
RDX: 0000000000000000 RSI: ffffffff8dba5d5f RDI: ffffffff8be33300
RBP: ffffffff8172c195 R08: 0000000000000000 R09: ffffffff8172c195
R10: ffffc90000a081b8 R11: ffffffff81ac3910 R12: 0000000000000002
R13: ffffffff8e139ea0 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:330 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4236
 __skb_ext_alloc net/core/skbuff.c:6976 [inline]
 skb_ext_add+0x148/0x8f0 net/core/skbuff.c:7079
 nf_bridge_alloc include/net/netfilter/br_netfilter.h:12 [inline]
 br_nf_pre_routing_ipv6+0x132/0x6b0 net/bridge/br_netfilter_ipv6.c:172
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:283 [inline]
 br_handle_frame+0x982/0x14c0 net/bridge/br_input.c:434
 __netif_receive_skb_core+0x10b9/0x4020 net/core/dev.c:5878
 __netif_receive_skb_one_core net/core/dev.c:5989 [inline]
 __netif_receive_skb+0x72/0x380 net/core/dev.c:6104
 process_backlog+0x60e/0x14f0 net/core/dev.c:6456
 __napi_poll+0xc7/0x360 net/core/dev.c:7506
 napi_poll net/core/dev.c:7569 [inline]
 net_rx_action+0x707/0xe30 net/core/dev.c:7696
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 do_softirq+0xec/0x180 kernel/softirq.c:480
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:910 [inline]
 __dev_queue_xmit+0x1d79/0x3b50 net/core/dev.c:4752
 dev_queue_xmit include/linux/netdevice.h:3361 [inline]
 neigh_hh_output include/net/neighbour.h:531 [inline]
 neigh_output include/net/neighbour.h:545 [inline]
 ip6_finish_output2+0x11bc/0x16a0 net/ipv6/ip6_output.c:141
 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
 mld_sendpack+0x800/0xd80 net/ipv6/mcast.c:1860
 ipv6_mc_dad_complete+0x88/0x410 net/ipv6/mcast.c:2284
 addrconf_dad_completed+0x6d5/0xd60 net/ipv6/addrconf.c:4340
 addrconf_dad_work+0xc36/0x14b0 net/ipv6/addrconf.c:-1
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g11409 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3567
rcu: rcu_preempt kthread starved for 10502 jiffies! g11409 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:27160 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7058
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>