------------[ cut here ]------------
'send_pkt()' returns 0, but 4096 expected
WARNING: net/vmw_vsock/virtio_transport_common.c:431 at virtio_transport_send_pkt_info+0xd94/0xff0 net/vmw_vsock/virtio_transport_common.c:429, CPU#1: syz.0.17/5999
Modules linked in:
CPU: 1 UID: 0 PID: 5999 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:virtio_transport_send_pkt_info+0xd99/0xff0 net/vmw_vsock/virtio_transport_common.c:429
Code: fc ff df e9 0d fe ff ff e8 54 02 38 f6 b0 01 49 bf 00 00 00 00 00 fc ff df e9 28 f7 ff ff 48 8d 3d 1c 29 96 04 89 ee 4c 89 e2 <67> 48 0f b9 3a 31 ff 44 89 f6 e8 68 06 38 f6 45 85 f6 4c 8b 6c 24
RSP: 0018:ffffc90003807538 EFLAGS: 00010206
RAX: ffffffff8b8da830 RBX: ffffffff8b8e5680 RCX: 0000000000000000
RDX: 0000000000001000 RSI: 0000000000000000 RDI: ffffffff9023d550
RBP: 0000000000000000 R08: ffffffff9011beb7 R09: 1ffffffff20237d6
R10: dffffc0000000000 R11: fffffbfff20237d7 R12: 0000000000001000
R13: ffffc90003807660 R14: 0000000000001000 R15: dffffc0000000000
FS:  0000555561832500(0000) GS:ffff88812555a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000030000 CR3: 000000007874c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 virtio_transport_stream_enqueue net/vmw_vsock/virtio_transport_common.c:1123 [inline]
 virtio_transport_seqpacket_enqueue+0x1b4/0x250 net/vmw_vsock/virtio_transport_common.c:850
 vsock_connectible_sendmsg+0xad6/0x1070 net/vmw_vsock/af_vsock.c:2267
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
 __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2735
 __do_sys_sendmmsg net/socket.c:2762 [inline]
 __se_sys_sendmmsg net/socket.c:2759 [inline]
 __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2759
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f406f79c799
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:00007fff17795508 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f406fa15fa0 RCX: 00007f406f79c799
RDX: 0000000000000001 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007f406f832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000024008094 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f406fa15fac R14: 00007f406fa15fa0 R15: 00007f406fa15fa0
 </TASK>
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	e9 0d fe ff ff       	jmp    0xfffffe12
   5:	e8 54 02 38 f6       	call   0xf638025e
   a:	b0 01                	mov    $0x1,%al
   c:	49 bf 00 00 00 00 00 	movabs $0xdffffc0000000000,%r15
  13:	fc ff df
  16:	e9 28 f7 ff ff       	jmp    0xfffff743
  1b:	48 8d 3d 1c 29 96 04 	lea    0x496291c(%rip),%rdi        # 0x496293e
  22:	89 ee                	mov    %ebp,%esi
  24:	4c 89 e2             	mov    %r12,%rdx
* 27:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2c:	31 ff                	xor    %edi,%edi
  2e:	44 89 f6             	mov    %r14d,%esi
  31:	e8 68 06 38 f6       	call   0xf638069e
  36:	45 85 f6             	test   %r14d,%r14d
  39:	4c                   	rex.WR
  3a:	8b                   	.byte 0x8b
  3b:	6c                   	insb   (%dx),%es:(%rdi)
  3c:	24                   	.byte 0x24