------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 15032 at lib/refcount.c:25 refcount_warn_saturate+0xfa/0x1d0
Modules linked in:
CPU: 0 UID: 0 PID: 15032 Comm: syz.1.2132 Not tainted 6.16.0-rc3-syzkaller-00159-g223e2288f4b8 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:refcount_warn_saturate+0xfa/0x1d0
Code: 00 00 e8 89 d2 fe fc 5b 41 5e c3 cc cc cc cc cc e8 7b d2 fe fc c6 05 fe 8b c9 0a 01 90 48 c7 c7 c0 42 e2 8b e8 f7 7a c2 fc 90 <0f> 0b 90 90 eb d7 e8 5b d2 fe fc c6 05 df 8b c9 0a 01 90 48 c7 c7
RSP: 0018:ffffc900075d7c88 EFLAGS: 00010246
RAX: 0760cca50e1aa700 RBX: 0000000000000002 RCX: ffff88811add1cc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc900075d7d90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfaa04 R12: 1ffff1100667d205
R13: 1ffff92000ebaf9c R14: ffff88810c6bfcc8 R15: dffffc0000000000
FS:  00007fd8dcc9b6c0(0000) GS:ffff8880b8650000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd8dcc58fc8 CR3: 0000000026082000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ax25_setsockopt+0xabb/0xc20
 do_sock_setsockopt+0x25a/0x3e0
 __x64_sys_setsockopt+0x18b/0x220
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd8dbd8e929
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:00007fd8dcc9b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007fd8dbfb5fa0 RCX: 00007fd8dbd8e929
RDX: 0000000000000019 RSI: 0000000000000101 RDI: 00000000000000cd
RBP: 00007fd8dbe10b39 R08: 0000000000000010 R09: 0000000000000000
R10: 00002000000001c0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd8dbfb5fa0 R15: 00007ffdfa8908d8
 </TASK>
