I stumbled on a bug in qemu 4.2.0 (virsh 6.0.0) with a large number of overlays. I am using "qemu-img create" and "virsh snapshot-create-as" to create each overlay. When I run "virsh snapshot-create-as" for the 42nd overlay, I get "error: No complete monitor response found in 10485760 bytes: Numerical result out of range". However, I pulled down qemu 5.1.50 (still using virsh 6.0.0), and it looks like the problem has disappeared which is great. Does anyone know the patch set that addressed this bug? Also, does anyone know the "official" limit on the number of overlays that can be created and is there a qemu test that exercises this? I could not find an overlay limit test in tests/qemu-iotests.