syzbot

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refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 0 PID: 26606 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31
Modules linked in:
CPU: 0 PID: 26606 Comm: kworker/u4:2 Not tainted 5.16.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31
Code: 1d 98 f3 a1 09 31 ff 89 de e8 1d f2 9c fd 84 db 75 e0 e8 34 ee 9c fd 48 c7 c7 e0 d4 04 8a c6 05 78 f3 a1 09 01 e8 5b a5 25 05 <0f> 0b eb c4 e8 18 ee 9c fd 0f b6 1d 67 f3 a1 09 31 ff 89 de e8 e8
RSP: 0018:ffffc90004b3f918 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888022c8ba00 RSI: ffffffff815f0c28 RDI: fffff52000967f15
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815ea9ce R11: 0000000000000000 R12: ffff888020dfd800
R13: 0000000000000001 R14: ffff88807f28c5b0 R15: ffffffff8d74d320
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055897eab8fd7 CR3: 00000000141e3000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 __refcount_dec include/linux/refcount.h:344 [inline]
 refcount_dec include/linux/refcount.h:359 [inline]
 dev_put include/linux/netdevice.h:4166 [inline]
 batadv_hardif_release net/batman-adv/hard-interface.c:52 [inline]
 kref_put include/linux/kref.h:65 [inline]
 batadv_hardif_put net/batman-adv/hard-interface.h:95 [inline]
 batadv_hard_if_event+0x128a/0x1600 net/batman-adv/hard-interface.c:985
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2002
 call_netdevice_notifiers_extack net/core/dev.c:2014 [inline]
 call_netdevice_notifiers net/core/dev.c:2028 [inline]
 unregister_netdevice_many+0x94f/0x1790 net/core/dev.c:11077
 default_device_exit_batch+0x2fa/0x3c0 net/core/dev.c:11607
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:171
 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:593
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>