syzbot

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 0 UID: 0 PID: 13072 Comm: syz.3.1274 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:handshake_complete+0x31/0x390 net/handshake/request.c:290
Code: 56 41 55 49 89 d5 41 54 41 89 f4 55 53 48 89 fb e8 d4 3e 57 f6 48 8d 7b 28 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 0f 03 00 00 48 8b 6b 28 e8 1c 3b 0e 00 48 b8 00
RSP: 0018:ffffc90003d574f8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000005 RSI: ffffffff8b672c1c RDI: 0000000000000028
RBP: ffffc90003d575c0 R08: 0000000000000000 R09: ffffed102827ec80
R10: ffff8881413f6403 R11: 0000000000000001 R12: 00000000fffffffb
R13: 0000000000000000 R14: ffff88807983dd40 R15: ffff88802b47a5c0
FS:  00007f1c2a82a6c0(0000) GS:ffff8881248fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1c2a7e7f98 CR3: 000000007c97a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 handshake_nl_accept_doit+0x30f/0x930 net/handshake/netlink.c:129
 genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
 __sys_sendmsg+0x16d/0x220 net/socket.c:2678
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c2998f7c9
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:00007f1c2a82a038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1c29be6180 RCX: 00007f1c2998f7c9
RDX: 000000002004881c RSI: 0000200000000580 RDI: 0000000000000004
RBP: 00007f1c29a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1c29be6218 R14: 00007f1c29be6180 R15: 00007ffff33035f8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:handshake_complete+0x31/0x390 net/handshake/request.c:290
Code: 56 41 55 49 89 d5 41 54 41 89 f4 55 53 48 89 fb e8 d4 3e 57 f6 48 8d 7b 28 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 0f 03 00 00 48 8b 6b 28 e8 1c 3b 0e 00 48 b8 00
RSP: 0018:ffffc90003d574f8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000005 RSI: ffffffff8b672c1c RDI: 0000000000000028
RBP: ffffc90003d575c0 R08: 0000000000000000 R09: ffffed102827ec80
R10: ffff8881413f6403 R11: 0000000000000001 R12: 00000000fffffffb
R13: 0000000000000000 R14: ffff88807983dd40 R15: ffff88802b47a5c0
FS:  00007f1c2a82a6c0(0000) GS:ffff8881248fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f68820b4286 CR3: 000000007c97a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	56                   	push   %rsi
   1:	41 55                	push   %r13
   3:	49 89 d5             	mov    %rdx,%r13
   6:	41 54                	push   %r12
   8:	41 89 f4             	mov    %esi,%r12d
   b:	55                   	push   %rbp
   c:	53                   	push   %rbx
   d:	48 89 fb             	mov    %rdi,%rbx
  10:	e8 d4 3e 57 f6       	call   0xf6573ee9
  15:	48 8d 7b 28          	lea    0x28(%rbx),%rdi
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 0f 03 00 00    	jne    0x343
  34:	48 8b 6b 28          	mov    0x28(%rbx),%rbp
  38:	e8 1c 3b 0e 00       	call   0xe3b59
  3d:	48                   	rex.W
  3e:	b8                   	.byte 0xb8