Subject: [syzbot] [net?] kernel BUG in pn_socket_autobind

From: syzbot <[email-masked]>
Date: Tue, 21 Apr 2026 08:35:32 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    b4e07588e743 tracing: tell git to ignore the generated 'un..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10aa8e6a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=95ee3fe1c5a8ab57
dashboard link: https://syzkaller.appspot.com/bug?extid=b3c0e6a240078433c42b
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-b4e07588.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bb7067cc2bb4/vmlinux-b4e07588.xz
kernel image: https://storage.googleapis.com/syzbot-assets/46b9d3bae153/bzImage-b4e07588.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

netlink: 'syz.3.104': attribute type 2 has an invalid length.
------------[ cut here ]------------
kernel BUG at net/phonet/socket.c:213!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 6429 Comm: syz.3.104 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:pn_socket_autobind net/phonet/socket.c:213 [inline]
RIP: 0010:pn_socket_autobind+0x14c/0x170 net/phonet/socket.c:202
Code: 00 00 00 00 48 8b 44 24 58 65 48 2b 05 35 85 47 09 75 2a 48 83 c4 60 89 d8 5b 5d 41 5c 41 5d c3 cc cc cc cc e8 f5 0f 3d f7 90 <0f> 0b e8 ad c8 aa f7 eb 9e e8 06 c9 aa f7 e9 6c ff ff ff e8 5c b0
RSP: 0018:ffffc900037ffa30 EFLAGS: 00010287
RAX: 000000000000084d RBX: 0000000000000000 RCX: ffffc90007544000
RDX: 0000000000080000 RSI: ffffffff8acc6aeb RDI: ffff888034de8000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff920006fff46
R13: dffffc0000000000 R14: 1ffff920006fff61 R15: ffffc900037ffe48
FS:  00007fdb20e7f6c0(0000) GS:ffff8880d63e1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fce31d5ee9c CR3: 000000002d58c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 pn_socket_sendmsg+0x43/0xe0 net/phonet/socket.c:421
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
 __sys_sendmsg+0x170/0x220 net/socket.c:2784
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdb1ff9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdb20e7f028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fdb20215fa0 RCX: 00007fdb1ff9c819
RDX: 0000000000008000 RSI: 0000200000000380 RDI: 0000000000000006
RBP: 00007fdb20032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdb20216038 R14: 00007fdb20215fa0 R15: 00007ffc7b77c6b8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:pn_socket_autobind net/phonet/socket.c:213 [inline]
RIP: 0010:pn_socket_autobind+0x14c/0x170 net/phonet/socket.c:202
Code: 00 00 00 00 48 8b 44 24 58 65 48 2b 05 35 85 47 09 75 2a 48 83 c4 60 89 d8 5b 5d 41 5c 41 5d c3 cc cc cc cc e8 f5 0f 3d f7 90 <0f> 0b e8 ad c8 aa f7 eb 9e e8 06 c9 aa f7 e9 6c ff ff ff e8 5c b0
RSP: 0018:ffffc900037ffa30 EFLAGS: 00010287
RAX: 000000000000084d RBX: 0000000000000000 RCX: ffffc90007544000
RDX: 0000000000080000 RSI: ffffffff8acc6aeb RDI: ffff888034de8000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff920006fff46
R13: dffffc0000000000 R14: 1ffff920006fff61 R15: ffffc900037ffe48
FS:  00007fdb20e7f6c0(0000) GS:ffff8880d63e1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fce31d5ee9c CR3: 000000002d58c000 CR4: 0000000000352ef0

---
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