migration-tests hangs intermittently for me, and git bisect led me here. Test script:
i=0; while true; do let i++; echo "= $i =";
MALLOC_PERTURB_=${MALLOC_PERTURB_:-$(( ${RANDOM:-0} % 255 + 1))}
QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 QTEST_QEMU_IMG=qemu-img
tests/migration-test -p /x86_64/migration/postcopy/recovery -k; done
