============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
kworker/u4:3/895 is trying to acquire lock:
ffffffff8d43cb48 (rtnl_mutex){+.+.}-{3:3}, at: ip_mc_drop_socket+0x7b/0x270 net/ipv4/igmp.c:2702

but task is already holding lock:
ffffffff8d43cb48 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_delete_nets+0xd0/0x370 net/ipv4/ip_tunnel.c:1132

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rtnl_mutex);
  lock(rtnl_mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

4 locks held by kworker/u4:3/895:
 #0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900038cfd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffffffff8d430c50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
 #3: ffffffff8d43cb48 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_delete_nets+0xd0/0x370 net/ipv4/ip_tunnel.c:1132

stack backtrace:
CPU: 0 PID: 895 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 __lock_acquire+0x1236/0x7d10 kernel/locking/lockdep.c:-1
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 ip_mc_drop_socket+0x7b/0x270 net/ipv4/igmp.c:2702
 inet_release+0x47/0x180 net/ipv4/af_inet.c:419
 __sock_release net/socket.c:651 [inline]
 sock_release+0x7b/0x140 net/socket.c:679
 vxlan_sock_release+0x385/0x400 drivers/net/vxlan/vxlan_core.c:1637
 vxlan_stop+0xf62/0x1090 drivers/net/vxlan/vxlan_core.c:3149
 __dev_close_many+0x1d3/0x2b0 net/core/dev.c:1634
 dev_close_many+0x21f/0x400 net/core/dev.c:1659
 unregister_netdevice_many+0x481/0x19f0 net/core/dev.c:11136
 vxlan_handle_lowerdev_unregister drivers/net/vxlan/vxlan_core.c:4529 [inline]
 vxlan_netdevice_event+0x2cb/0x310 drivers/net/vxlan/vxlan_core.c:4539
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 unregister_netdevice_many+0x1049/0x19f0 net/core/dev.c:11160
 ip_tunnel_delete_nets+0x320/0x370 net/ipv4/ip_tunnel.c:1137
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x791/0xba0 net/core/net_namespace.c:635
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>