'send_pkt()' returns 0, but 65536 expected
WARNING: CPU: 3 PID: 7228 at net/vmw_vsock/virtio_transport_common.c:426 virtio_transport_send_pkt_info+0x91d/0x1020 net/vmw_vsock/virtio_transport_common.c:426
Modules linked in:
CPU: 3 UID: 0 PID: 7228 Comm: syz.1.506 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:virtio_transport_send_pkt_info+0x91d/0x1020 net/vmw_vsock/virtio_transport_common.c:426
Code: a9 16 48 f6 84 db 75 26 e8 c0 1b 48 f6 c6 05 72 35 20 05 01 90 48 8b 54 24 10 44 89 ee 48 c7 c7 00 4b 13 8d e8 24 bc 06 f6 90 <0f> 0b 90 90 e8 9a 1b 48 f6 31 ff 44 89 e6 e8 d0 16 48 f6 45 85 e4
RSP: 0018:ffffc90006757730 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90007b62000
RDX: 0000000000080000 RSI: ffffffff817a3365 RDI: 0000000000000001
RBP: ffff888056f47000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 6b705f646e657327 R12: 0000000000010000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000010000
FS:  00007f46b7e906c0(0000) GS:ffff8880d69bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000003f000 CR3: 00000000555c6000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 virtio_transport_stream_enqueue net/vmw_vsock/virtio_transport_common.c:1111 [inline]
 virtio_transport_seqpacket_enqueue+0x13c/0x1c0 net/vmw_vsock/virtio_transport_common.c:839
 vsock_connectible_sendmsg+0xfa1/0x1280 net/vmw_vsock/af_vsock.c:2141
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg net/socket.c:729 [inline]
 ____sys_sendmsg+0xa95/0xc70 net/socket.c:2614
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2668
 __sys_sendmmsg+0x200/0x420 net/socket.c:2757
 __do_sys_sendmmsg net/socket.c:2784 [inline]
 __se_sys_sendmmsg net/socket.c:2781 [inline]
 __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2781
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f46b6f8ebe9
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:00007f46b7e90038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f46b71b5fa0 RCX: 00007f46b6f8ebe9
RDX: 0000000000000001 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007f46b7011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000024008094 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f46b71b6038 R14: 00007f46b71b5fa0 R15: 00007ffdc3186048
 </TASK>