syzbot

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refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 1 PID: 10099 at lib/refcount.c:31 refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
Modules linked in:
CPU: 0 PID: 10099 Comm: kworker/u4:44 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: netns cleanup_net
RIP: 0010:refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
Code: 05 5a 60 51 0a 01 e8 35 0a b5 05 0f 0b e9 d3 fe ff ff e8 6c 9b 75 fd 48 c7 c7 c0 6d a6 8a c6 05 37 60 51 0a 01 e8 16 0a b5 05 <0f> 0b e9 b4 fe ff ff 48 89 ef e8 5a b5 c3 fd e9 5c fe ff ff 0f 1f
RSP: 0018:ffffc9000b2e77d8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88808dd90000 RSI: ffffffff8166b1dc RDI: fffff5200165ceed
RBP: ffff88808699e600 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: 1ffff9200165cf00
R13: 0000000000000000 R14: ffff88808699e600 R15: ffffffff8e536c40
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555555cd16e8 CR3: 0000000028984000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_dec include/linux/refcount.h:344 [inline]
 refcount_dec include/linux/refcount.h:359 [inline]
 ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
 netdev_tracker_free include/linux/netdevice.h:4039 [inline]
 netdev_put include/linux/netdevice.h:4056 [inline]
 dev_put include/linux/netdevice.h:4082 [inline]
 batadv_hardif_release+0x60/0xe0 net/batman-adv/hard-interface.c:53
 kref_put include/linux/kref.h:65 [inline]
 batadv_hardif_put net/batman-adv/hard-interface.h:95 [inline]
 batadv_hard_if_event+0xcd0/0x1450 net/batman-adv/hard-interface.c:1002
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1944
 call_netdevice_notifiers_extack net/core/dev.c:1982 [inline]
 call_netdevice_notifiers net/core/dev.c:1996 [inline]
 unregister_netdevice_many_notify+0xa2b/0x19e0 net/core/dev.c:10839
 unregister_netdevice_many net/core/dev.c:10895 [inline]
 default_device_exit_batch+0x451/0x590 net/core/dev.c:11348
 ops_exit_list+0x125/0x170 net/core/net_namespace.c:174
 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:606
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>