------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 9456 at lib/refcount.c:25 refcount_warn_saturate+0x13a/0x1d0 lib/refcount.c:25
Modules linked in:
CPU: 0 UID: 0 PID: 9456 Comm: syz.2.919 Not tainted 6.15.0-rc1-syzkaller-00209-gfaeefc173be4 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:refcount_warn_saturate+0x13a/0x1d0 lib/refcount.c:25
Code: 00 6b a1 8c e8 17 87 7d fc 90 0f 0b 90 90 eb b9 e8 0b 65 be fc c6 05 94 dc 44 0b 01 90 48 c7 c7 60 6b a1 8c e8 f7 86 7d fc 90 <0f> 0b 90 90 eb 99 e8 eb 64 be fc c6 05 75 dc 44 0b 01 90 48 c7 c7
RSP: 0018:ffffc9000afe7c68 EFLAGS: 00010246
RAX: fba988da59282e00 RBX: ffff8880790be0c8 RCX: 0000000000080000
RDX: ffffc9000d870000 RSI: 00000000000034d7 RDI: 00000000000034d8
RBP: 0000000000000002 R08: ffffffff81828a12 R09: fffffbfff1d7a978
R10: dffffc0000000000 R11: fffffbfff1d7a978 R12: 1ffff1100c9ae605
R13: ffff8880790be000 R14: ffff88807b098000 R15: ffff888064d73028
FS:  00007fc879c496c0(0000) GS:ffff888124f93000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30b0bff8 CR3: 00000000560f2000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ax25_setsockopt+0xbb7/0xf00 net/ax25/af_ax25.c:705
 do_sock_setsockopt+0x3b1/0x710 net/socket.c:2296
 __sys_setsockopt net/socket.c:2321 [inline]
 __do_sys_setsockopt net/socket.c:2327 [inline]
 __se_sys_setsockopt net/socket.c:2324 [inline]
 __x64_sys_setsockopt+0x1ee/0x280 net/socket.c:2324
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc878d8d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc879c49038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007fc878fa6080 RCX: 00007fc878d8d169
RDX: 0000000000000019 RSI: 0000000000000101 RDI: 0000000000000008
RBP: 00007fc878e0e990 R08: 0000000000000010 R09: 0000000000000000
R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc878fa6080 R15: 00007ffc22224308
 </TASK>