[syzbot] [net?] general protection fault in dev_set_group

[syzbot <syzbot+9fc858ba0312b42b577e@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    b56bbaf8c9ff Merge branch 'net-airoha-fix-ipv6-hw-accelera..
git tree:       net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11947c82580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=262b2977ef00756b
dashboard link: https://syzkaller.appspot.com/bug?extid=9fc858ba0312b42b577e
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1122780c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15947c82580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dfc603506ef3/disk-b56bbaf8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/531e9b9a7cff/vmlinux-b56bbaf8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/001a9016bbc6/bzImage-b56bbaf8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9fc858ba0312b42b577e@syzkaller.appspotmail.com

netlink: 'syz-executor579': attribute type 1 has an invalid length.
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000055: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000002a8-0x00000000000002af]
CPU: 1 UID: 0 PID: 5834 Comm: syz-executor579 Not tainted 6.15.0-syzkaller-07817-gb56bbaf8c9ff #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]
RIP: 0010:netdev_lock_ops include/net/netdev_lock.h:41 [inline]
RIP: 0010:dev_set_group+0xc0/0x230 net/core/dev_api.c:82
Code: 03 43 80 3c 2f 00 74 08 48 89 df e8 4a 40 d4 f8 41 bd a8 02 00 00 4c 03 2b 4c 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ef e8 22 40 d4 f8 31 c0 49 83 7d 00 00 0f
RSP: 0018:ffffc9000417ee60 EFLAGS: 00010206
RAX: 0000000000000055 RBX: ffff8880227e4008 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000055690764 RDI: ffff8880227e4000
RBP: ffff8880227e4000 R08: 0000000000400dc0 R09: 00000000ffffffff
R10: dffffc0000000000 R11: fffffbfff1f41637 R12: 0000000000000000
R13: 00000000000002a8 R14: 1ffff110044fc998 R15: 1ffff110044fc801
FS:  000055556089f380(0000) GS:ffff888125d66000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563942114448 CR3: 000000007d85a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rtnl_create_link+0x748/0xd10 net/core/rtnetlink.c:3674
 rtnl_newlink_create+0x25c/0xb00 net/core/rtnetlink.c:3813
 __rtnl_newlink net/core/rtnetlink.c:3940 [inline]
 rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4055
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x75b/0x8d0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 ____sys_sendmsg+0x505/0x830 net/socket.c:2566
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2655
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa5080a6369
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd3dfbc8b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffd3dfbca88 RCX: 00007fa5080a6369
RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000003
RBP: 00007fa508119610 R08: 0000000000000000 R09: 00007ffd3dfbca88
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd3dfbca78 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]
RIP: 0010:netdev_lock_ops include/net/netdev_lock.h:41 [inline]
RIP: 0010:dev_set_group+0xc0/0x230 net/core/dev_api.c:82
Code: 03 43 80 3c 2f 00 74 08 48 89 df e8 4a 40 d4 f8 41 bd a8 02 00 00 4c 03 2b 4c 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ef e8 22 40 d4 f8 31 c0 49 83 7d 00 00 0f
RSP: 0018:ffffc9000417ee60 EFLAGS: 00010206
RAX: 0000000000000055 RBX: ffff8880227e4008 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000055690764 RDI: ffff8880227e4000
RBP: ffff8880227e4000 R08: 0000000000400dc0 R09: 00000000ffffffff
R10: dffffc0000000000 R11: fffffbfff1f41637 R12: 0000000000000000
R13: 00000000000002a8 R14: 1ffff110044fc998 R15: 1ffff110044fc801
FS:  000055556089f380(0000) GS:ffff888125c66000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045ad50 CR3: 000000007d85a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	03 43 80             	add    -0x80(%rbx),%eax
   3:	3c 2f                	cmp    $0x2f,%al
   5:	00 74 08 48          	add    %dh,0x48(%rax,%rcx,1)
   9:	89 df                	mov    %ebx,%edi
   b:	e8 4a 40 d4 f8       	call   0xf8d4405a
  10:	41 bd a8 02 00 00    	mov    $0x2a8,%r13d
  16:	4c 03 2b             	add    (%rbx),%r13
  19:	4c 89 e8             	mov    %r13,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 ef             	mov    %r13,%rdi
  33:	e8 22 40 d4 f8       	call   0xf8d4405a
  38:	31 c0                	xor    %eax,%eax
  3a:	49 83 7d 00 00       	cmpq   $0x0,0x0(%r13)
  3f:	0f                   	.byte 0xf


---
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