Description of problem:
When I run qemu and immediately use QMP it coredumps.

Version-Release number of selected component (if applicable):
qemu-kvm-1.0.1-4.fc17.x86_64
kernel-3.8.3-103.fc17.x86_64

How reproducible:
Always

Steps to Reproduce:
1. echo -e '{ "execute": "qmp_capabilities" }\n{ "execute": "query-commands" }\n{ "execute": "quit" }' | qemu-kvm -qmp stdio
  
Actual results:
Segmentation fault (core dumped)

Expected results:
List the supported qmp commands and exit.

Additional info:
I can also reproduce this with qemu-kvm -qmp unix:/tmp/aaa,server (without nowait) and echo '{ "execute": "qmp_capabilities" }' | socat unix:/tmp/aaa -
When I use nowait and delay the write even for 0.01s sleep it works fine.