[v6.1] WARNING: refcount bug in ax25_release

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ae9f2a70d69e Linux 6.1.93
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17146851980000
kernel config: https://syzkaller.appspot.com/x/.config?x=1d7ac9fef66f54aa
dashboard link: https://syzkaller.appspot.com/bug?extid=7ed59d42e7f489c36a83
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b6a79d8f90ec/disk-ae9f2a70.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f1b3e75b81f1/vmlinux-ae9f2a70.xz
kernel image: https://storage.googleapis.com/syzbot-assets/80fc2213e3e5/bzImage-ae9f2a70.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7ed59d...@syzkaller.appspotmail.com

------------[ cut here ]------------
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 0 PID: 16004 at lib/refcount.c:31 refcount_warn_saturate+0x16d/0x1a0 lib/refcount.c:31
Modules linked in:
CPU: 0 PID: 16004 Comm: syz-executor.1 Not tainted 6.1.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:refcount_warn_saturate+0x16d/0x1a0 lib/refcount.c:31
Code: c7 c7 00 09 3d 8b e8 e2 39 1a fd 0f 0b e9 6e ff ff ff e8 96 3c 52 fd c6 05 31 42 27 0a 01 48 c7 c7 60 09 3d 8b e8 c3 39 1a fd <0f> 0b e9 4f ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c b2 fe ff
RSP: 0018:ffffc9000399fb48 EFLAGS: 00010246
RAX: de4416b10cf8aa00 RBX: 0000000000000004 RCX: ffff88801f788000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000004 R08: ffffffff815292de R09: fffff52000733ec9
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88807ac6e5b8
R13: 0000000000000000 R14: ffff88807ac6e5fc R15: dffffc0000000000
FS: 00005555572f0480(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5f245f6000 CR3: 0000000022e7c000 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]
ref_tracker_free+0x6a0/0x7d0 lib/ref_tracker.c:118
netdev_tracker_free include/linux/netdevice.h:4028 [inline]
netdev_put include/linux/netdevice.h:4045 [inline]
ax25_release+0x3ef/0x940 net/ax25/af_ax25.c:1069
__sock_release net/socket.c:654 [inline]
sock_close+0xcd/0x230 net/socket.c:1400
__fput+0x3b7/0x890 fs/file_table.c:320
task_work_run+0x246/0x300 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f85b367cea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffca625378 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00000000000cfd37 RCX: 00007f85b367cea9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: ffffffffffffffff R08: 0000000000000001 R09: 0000000300000000
R10: 00007f85b3600000 R11: 0000000000000246 R12: 00007f85b37b3f80
R13: 00007f85b37b3f8c R14: 0000000000000032 R15: 00007f85b37b5980
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup