QEMU crash after send data from Host through serial port 

Hi All

I have two computer, one is Win7 32 another is Win7 64, Both computer meet this issue.
My QEMU version is qemu-w32-setup-20160215

I want used EDK2 OVMF with Intel UDK Debugger tools to do source level debug
I had install com0com Virtual Com Port, and set COM3 connect to COM4

Intel UDK Debugger tools used COM3
QEMU run OVMF used COM4

First execute Intel UDK Debugger tools, then launch QEMU
C:\Program Files\qemu\qemu-system-x86_64.exe -bios "C:\EDK2\Build\OvmfX64\DEBUG_VS2010\FV\OVMF.fd" -serial COM4
Then QEMU crashes on stratup

I have do some experiment
Execute terminal tool Tera Term and used COM3
launch QEMU and used COM4
C:\Program Files\qemu\qemu-system-x86_64.exe -bios "C:\EDK2\Build\OvmfX64\DEBUG_VS2010\FV\OVMF.fd" -serial COM4
This is fine and i can see OVMF trace log on terminal
But if i press "Down" key on terminal, then QEMU crashe
It's caused by terminal send data("Down" key) to QEMU

Have somebody can share some information about this?

Thanks a lot.
Sugar