------------[ cut here ]------------
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 0 PID: 31093 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31
Modules linked in:
CPU: 0 PID: 31093 Comm: kworker/u4:1 Not tainted 5.15.0-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 9e 9c 81 09 31 ff 89 de e8 6d 11 9d fd 84 db 75 e0 e8 84 0d 9d fd 48 c7 c7 60 cb e4 89 c6 05 7e 9c 81 09 01 e8 78 77 1c 05 <0f> 0b eb c4 e8 68 0d 9d fd 0f b6 1d 6d 9c 81 09 31 ff 89 de e8 38
RSP: 0018:ffffc90004187a50 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888020a03a00 RSI: ffffffff815f39c8 RDI: fffff52000830f3c
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815ed79e R11: 0000000000000000 R12: 0000000000000001
R13: ffffc90004187bb8 R14: ffff8880135e45b0 R15: ffff888070aee5a0
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efd0b695558 CR3: 000000001b0ad000 CR4: 00000000003506f0
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]
 dev_put include/linux/netdevice.h:4166 [inline]
 unregister_netdevice_many+0x12c9/0x1790 net/core/dev.c:11114
 ip6gre_exit_batch_net+0x4a7/0x760 net/ipv6/ip6_gre.c:1629
 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>