rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P17226/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=73345, q=1990 ncpus=2)
task:syz.5.2442      state:R  running task     stack:27112 pid:17226 tgid:17218 ppid:12315  task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_read_lock include/linux/rcupdate.h:842 [inline]
RIP: 0010:class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
RIP: 0010:unwind_next_frame+0xa3b/0x20a0 arch/x86/kernel/unwind_orc.c:479
Code: 6d f9 ff ff 80 3d f4 13 71 12 00 0f 85 60 f9 ff ff 4c 89 ef c6 05 e4 13 71 12 01 e8 cf f0 ff ff e9 4c f9 ff ff e8 45 c4 35 00 <84> c0 0f 85 9c f6 ff ff e8 68 c2 27 0a 85 c0 0f 84 8f f6 ff ff 80
RSP: 0018:ffffc9000eaa72b0 EFLAGS: 00000286
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 000000008f942b80
RDX: 0000000000000000 RSI: ffffffff8c161100 RDI: ffffffff8df5ce60
RBP: ffffc9000eaa7368 R08: ac212efc3f9d7c44 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000000 R12: ffffffff81a6dd60
R13: ffffc9000eaa7320 R14: 0000000000000000 R15: ffff888050dd0000
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x160/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895
 discard_slab mm/slub.c:2753 [inline]
 __put_partials+0x165/0x1c0 mm/slub.c:3218
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:340
 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_node_noprof+0x1d5/0x3b0 mm/slub.c:4281
 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:659
 alloc_skb include/linux/skbuff.h:1336 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 inet_netconf_notify_devconf+0x8b/0x1f0 net/ipv4/devinet.c:2210
 __devinet_sysctl_unregister net/ipv4/devinet.c:2705 [inline]
 devinet_sysctl_unregister net/ipv4/devinet.c:2729 [inline]
 inetdev_destroy net/ipv4/devinet.c:334 [inline]
 inetdev_event+0xed5/0x18a0 net/ipv4/devinet.c:1656
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 unregister_netdevice_many_notify+0xf76/0x24c0 net/core/dev.c:12148
 unregister_netdevice_many net/core/dev.c:12211 [inline]
 default_device_exit_batch+0x853/0xaf0 net/core/dev.c:12715
 ops_exit_list net/core/net_namespace.c:204 [inline]
 ops_undo_list+0x360/0xab0 net/core/net_namespace.c:251
 setup_net+0x1f1/0x380 net/core/net_namespace.c:453
 copy_net_ns+0x2a6/0x5f0 net/core/net_namespace.c:570
 create_new_namespaces+0x3ea/0xa90 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:218
 ksys_unshare+0x45b/0xa40 kernel/fork.c:3127
 __do_sys_unshare kernel/fork.c:3198 [inline]
 __se_sys_unshare kernel/fork.c:3196 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3196
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f873358ebe9
RSP: 002b:00007f87343bd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f87337b6270 RCX: 00007f873358ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000062040200
RBP: 00007f8733611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f87337b6308 R14: 00007f87337b6270 R15: 00007ffc389887b8
 </TASK>