------------[ cut here ]------------
'send_pkt()' returns 0, but 4096 expected
WARNING: net/vmw_vsock/virtio_transport_common.c:434 at virtio_transport_send_pkt_info+0xd0f/0xf30 net/vmw_vsock/virtio_transport_common.c:432, CPU#1: syz.0.17/5849
Modules linked in:
CPU: 1 UID: 0 PID: 5849 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:virtio_transport_send_pkt_info+0xd15/0xf30 net/vmw_vsock/virtio_transport_common.c:432
Code: cc cc e8 be dc 3e f6 31 ff 48 8b 74 24 08 ba 02 00 00 00 e8 cd 3c ee fd e9 0c ff ff ff 48 8d 3d 71 16 bc 04 44 89 fe 48 89 ea <67> 48 0f b9 3a 31 ff 44 89 f6 e8 cc e0 3e f6 45 85 f6 74 0a e8 82
RSP: 0018:ffffc90003357528 EFLAGS: 00010206
RAX: ffffffff8b86ccb2 RBX: ffffffff8b877950 RCX: 0000000000000000
RDX: 0000000000001000 RSI: 0000000000000000 RDI: ffffffff9042e600
RBP: 0000000000001000 R08: ffffffff9030a3f7 R09: 1ffffffff206147e
R10: dffffc0000000000 R11: fffffbfff206147f R12: ffffc90003357660
R13: dffffc0000000000 R14: 0000000000001000 R15: 0000000000000000
FS:  000055555d4bf500(0000) GS:ffff888125390000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000030000 CR3: 00000000753ac000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 virtio_transport_stream_enqueue net/vmw_vsock/virtio_transport_common.c:1125 [inline]
 virtio_transport_seqpacket_enqueue+0x1b4/0x250 net/vmw_vsock/virtio_transport_common.c:852
 vsock_connectible_sendmsg+0xad6/0x1070 net/vmw_vsock/af_vsock.c:2278
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752
 __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2841
 __do_sys_sendmmsg net/socket.c:2868 [inline]
 __se_sys_sendmmsg net/socket.c:2865 [inline]
 __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2865
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f53e319cdd9
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:00007ffdbca67888 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f53e3415fa0 RCX: 00007f53e319cdd9
RDX: 0000000000000001 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007f53e3232d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000024008094 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f53e3415fac R14: 00007f53e3415fa0 R15: 00007f53e3415fa0
 </TASK>
----------------
Code disassembly (best guess):
   0:	cc                   	int3
   1:	cc                   	int3
   2:	e8 be dc 3e f6       	call   0xf63edcc5
   7:	31 ff                	xor    %edi,%edi
   9:	48 8b 74 24 08       	mov    0x8(%rsp),%rsi
   e:	ba 02 00 00 00       	mov    $0x2,%edx
  13:	e8 cd 3c ee fd       	call   0xfdee3ce5
  18:	e9 0c ff ff ff       	jmp    0xffffff29
  1d:	48 8d 3d 71 16 bc 04 	lea    0x4bc1671(%rip),%rdi        # 0x4bc1695
  24:	44 89 fe             	mov    %r15d,%esi
  27:	48 89 ea             	mov    %rbp,%rdx
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	31 ff                	xor    %edi,%edi
  31:	44 89 f6             	mov    %r14d,%esi
  34:	e8 cc e0 3e f6       	call   0xf63ee105
  39:	45 85 f6             	test   %r14d,%r14d
  3c:	74 0a                	je     0x48
  3e:	e8                   	.byte 0xe8
  3f:	82                   	.byte 0x82