rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...0: (1 GPs behind) idle=4d34/1/0x4000000000000000 softirq=12919/12920 fqs=5248
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:        0          0            0
rcu: 	cputime:        0          0            0   ==> 52510(ms)
rcu: 	(detected by 0, t=10502 jiffies, g=11725, q=187 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3528 Comm: kworker/u4:11 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5492 [inline]
RIP: 0010:lock_is_held_type+0xb8/0x190 kernel/locking/lockdep.c:5825
Code: df 49 81 c7 e0 0a 00 00 45 31 e4 49 83 fc 31 73 24 4c 89 ff 4c 89 f6 e8 26 02 00 00 85 c0 75 2a 49 ff c4 48 63 83 d8 0a 00 00 <49> 83 c7 28 49 39 c4 7c d8 eb 11 48 c7 c7 60 d6 bf 8c 4c 89 e6 e8
RSP: 0018:ffffc900001f0cf8 EFLAGS: 00000002
RAX: 0000000000000006 RBX: ffff88802e5e3c00 RCX: 0000000000000000
RDX: ffff88802e5e3c00 RSI: ffff8880b8f2b718 RDI: ffff88802e5e4758
RBP: 00000000ffffffff R08: ffff88807b73e357 R09: 0000000000000000
R10: ffff88807b73e340 R11: ffffed100f6e7c6b R12: 0000000000000004
R13: 0000000000000046 R14: ffff8880b8f2b718 R15: ffff88802e5e4758
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000600 CR3: 000000000cb30000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 lock_is_held include/linux/lockdep.h:288 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1716 [inline]
 __hrtimer_run_queues+0x294/0xc40 kernel/time/hrtimer.c:1814
 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00
RSP: 0018:ffffc9000d1870c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0f00c2c5c9f26a00
RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc6f80
RBP: ffffc9000d1871c8 R08: dffffc0000000000 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: 1ffff92001a30e24
R13: ffffffff8d3d58a0 R14: 0000000000000246 R15: dffffc0000000000
 debug_objects_fill_pool+0x92/0x6b0 lib/debugobjects.c:615
 debug_object_assert_init+0x66/0x2f0 lib/debugobjects.c:894
 debug_timer_assert_init kernel/time/timer.c:792 [inline]
 debug_assert_init kernel/time/timer.c:837 [inline]
 __try_to_del_timer_sync+0x48/0x280 kernel/time/timer.c:1412
 __timer_delete_sync+0x1ff/0x2c0 kernel/time/timer.c:1574
 neigh_ifdown+0x1f/0x30 net/core/neighbour.c:465
 rt6_disable_ip+0x730/0x7a0 net/ipv6/route.c:4948
 addrconf_ifdown+0x15e/0x1880 net/ipv6/addrconf.c:3825
 addrconf_notify+0x6c6/0x1010 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x197/0x390 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
 call_netdevice_notifiers net/core/dev.c:2078 [inline]
 unregister_netdevice_many_notify+0xf36/0x1810 net/core/dev.c:11086
 ip6_tnl_exit_batch_net+0x5d3/0x620 net/ipv6/ip6_tunnel.c:2295
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x77f/0xb90 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>