[syzbot] [net?] WARNING in nsim_udp_tunnel_set_port

Hello,

syzbot found the following issue on:

HEAD commit:    63676eefb7a0 Merge tag 'sched_ext-for-6.13-rc5-fixes' of g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1336e418580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=86dd15278dbfe19f
dashboard link: https://syzkaller.appspot.com/bug?extid=2e5de9e3ab986b71d2bf
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17cfb1c4580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13ac4edf980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ba5dd9f6cf65/disk-63676eef.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/290bc4e6d798/vmlinux-63676eef.xz
kernel image: https://storage.googleapis.com/syzbot-assets/561f22e07925/bzImage-63676eef.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2e5de9e3ab986b71d2bf@syzkaller.appspotmail.com

------------[ cut here ]------------
entry already in use
WARNING: CPU: 1 PID: 5869 at drivers/net/netdevsim/udp_tunnels.c:26 nsim_udp_tunnel_set_port+0x2d3/0x390 drivers/net/netdevsim/udp_tunnels.c:26
Modules linked in:
CPU: 1 UID: 0 PID: 5869 Comm: syz-executor227 Not tainted 6.13.0-rc5-syzkaller-00161-g63676eefb7a0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:nsim_udp_tunnel_set_port+0x2d3/0x390 drivers/net/netdevsim/udp_tunnels.c:26
Code: c3 cc cc cc cc e8 dd a0 ca fa 44 89 f7 e8 85 38 b8 fa e9 ee fd ff ff e8 cb a0 ca fa 90 48 c7 c7 e0 7f 0a 8c e8 fe 66 8b fa 90 <0f> 0b 90 90 4c 8d 73 04 41 bf f0 ff ff ff e9 fa fe ff ff e8 c5 10
RSP: 0018:ffffc90003fffab8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffc90003fffbb0 RCX: ffffffff815a1789
RDX: ffff8880301d5a00 RSI: ffffffff815a1796 RDI: 0000000000000001
RBP: ffff8880744cc000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000017c10002 R15: 0000000000000000
FS:  0000555579af3380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ac84532b0 CR3: 000000001decc000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:225 [inline]
 udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:246 [inline]
 __udp_tunnel_nic_device_sync.part.0+0x935/0xed0 net/ipv4/udp_tunnel_nic.c:289
 __udp_tunnel_nic_device_sync net/ipv4/udp_tunnel_nic.c:283 [inline]
 __udp_tunnel_nic_reset_ntf+0x3c1/0x520 net/ipv4/udp_tunnel_nic.c:581
 udp_tunnel_nic_reset_ntf include/net/udp_tunnel.h:377 [inline]
 nsim_udp_tunnels_info_reset_write+0xc2/0x110 drivers/net/netdevsim/udp_tunnels.c:117
 full_proxy_write+0xfb/0x1b0 fs/debugfs/file.c:356
 vfs_write+0x24c/0x1150 fs/read_write.c:677
 ksys_write+0x12b/0x250 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5ac83d0df9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 1a 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc834f88c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f5ac83d0df9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f5ac841e1fa R09: 00007f5ac841e1fa
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5ac841e453
R13: 0000000000000001 R14: 00007ffc834f8900 R15: 0000000000000000
 </TASK>


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