Source: https://gitlab.com/qemu-project/qemu/-/issues/2707

1. 1. Host environment

• Operating system: Fedora 41
• OS/kernel version: 6.11.8-300.fc41.x86_64
• Architecture: x86_64
• QEMU flavor: All system emulators with virtio-balloon
• QEMU version: v9.2.0-rc2-34-g72b88908d1
• QEMU command line:
  ```
  ./qemu-system-x86_64 -device virtio-balloon,id=balloon -qmp qmp.sock
  ```

1. 1. Emulated/Virtualized environment

• Operating system: Any
• Architecture: All

1. 1. Description of problem

Fetch virtio-balloon stats will crash a QEMU crash with assert failures

1. 1. Steps to reproduce
      1. ./qemu-system-x86_64 -device virtio-balloon,id=balloon -qmp qmp.sock
      2. Connect to qmp.sock
      3. Issue 'qom-get path=/machine/peripheral/balloon property=guest-stats'
      4. QEMU go boom!

1. 1. Additional information

This is a regression caused by commit 0d2eeef77a33315187df8519491a900bde4a3d83, which failed to update `balloon_stat_names` with the new stats names, causing code to try to add a QDict entry with a NULL key.

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