rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P21139/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=198441, q=1896 ncpus=2)
task:syz.6.4299      state:R  running task     stack:25432 pid:21139 tgid:21138 ppid:17534  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 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:539 [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:on_stack arch/x86/include/asm/stacktrace.h:58 [inline]
RIP: 0010:unwind_next_frame+0x1a6a/0x2550 arch/x86/kernel/unwind_orc.c:694
Code: 6e 08 4d 8d 7e 10 4c 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 75 f6 b9 00 49 8b 07 4d 39 e5 0f 96 c1 4c 39 e0 0f 97 c2 <20> ca 80 fa 01 0f 85 63 01 00 00 49 8d 4c 24 08 4c 39 e9 0f 86 55
RSP: 0018:ffffc90003f16e18 EFLAGS: 00000216
RAX: ffffc90003f18000 RBX: ffffffff916c9401 RCX: 0000000000000001
RDX: ffffc90003f16f01 RSI: dffffc0000000000 RDI: ffffc90003f16ef0
RBP: dffffc0000000000 R08: ffffc90003f17f38 R09: 0000000000000000
R10: ffffc90003f16f38 R11: fffff520007e2de9 R12: ffffc90003f17f48
R13: ffffc90003f10000 R14: ffffc90003f16ee8 R15: ffffc90003f16ef8
 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
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 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_noprof+0x2bc/0x650 mm/slub.c:4905
 kmem_alloc_batch lib/debugobjects.c:371 [inline]
 fill_pool+0x156/0x580 lib/debugobjects.c:420
 debug_objects_fill_pool lib/debugobjects.c:742 [inline]
 debug_object_activate+0x4a3/0x580 lib/debugobjects.c:831
 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
 __call_rcu_common kernel/rcu/tree.c:3116 [inline]
 call_rcu+0x43/0x890 kernel/rcu/tree.c:3251
 __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]
 nlmsg_new include/net/netlink.h:1055 [inline]
 inet6_netconf_notify_devconf+0x10f/0x1d0 net/ipv6/addrconf.c:593
 __addrconf_sysctl_register+0x45a/0x4d0 net/ipv6/addrconf.c:7346
 addrconf_sysctl_register+0x168/0x1c0 net/ipv6/addrconf.c:7383
 ipv6_add_dev+0xd26/0x13a0 net/ipv6/addrconf.c:460
 addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3662
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 register_netdevice+0x18c9/0x1ec0 net/core/dev.c:11461
 register_netdev+0x40/0x60 net/core/dev.c:11539
 loopback_net_init+0x75/0x150 drivers/net/loopback.c:218
 ops_init+0x35c/0x5c0 net/core/net_namespace.c:137
 setup_net+0x118/0x340 net/core/net_namespace.c:446
 copy_net_ns+0x50e/0x730 net/core/net_namespace.c:579
 create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234
 ksys_unshare+0x57d/0x9f0 kernel/fork.c:3243
 __do_sys_unshare kernel/fork.c:3317 [inline]
 __se_sys_unshare kernel/fork.c:3315 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3315
 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: 0033:0x7fe90b19ce59
RSP: 002b:00007fe9093f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fe90b415fa0 RCX: 00007fe90b19ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000
RBP: 00007fe90b232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe90b416038 R14: 00007fe90b415fa0 R15: 00007fe90b53fa48
 </TASK>