====== Proxmox - Troubleshooting - Kernel Panic ======

Proxmox freezing with Kernel Panic.

This Kernel Panic seems to coincide with IO load.

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===== Possible Solution =====

Navigate to the specific VM causing the issue.

  * Select the **Hardware** menu.
  * Select the **Harddisk**.
  * Changing cache from **No cache** to **Write back**

  * Select **Memory** menu.
  * Uncheck **Ballooning device**.

<WRAP info>
**NOTE:**  As the Kernel Panic seems to coincide with IO load, another option is to try disabling **io_uring**.

  * With "cache=writeback" that is already the case, so it would seem to be a candidate of something that clearly changed in PVE 7.0.

  * To test, edit the VM config in **/etc/pve/qemu-server/<vmid>.conf**:
    * Add **,aio=native** to the end of your disks (i.e. scsi0, sata0, etc...).
    * Verify by making sure **<nowiki>qm showcmd 100 --pretty | grep io_uring</nowiki>** does not show anything.

</WRAP>

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===== Solution - Install the latest amd64_microcode =====

Edit **/etc/apt/sources.list**, and add in

<file bash /etc/apt/sources.list>
deb http://ftp.de.debian.org/debian bullseye main non-free
</file>

Install the AMD Microcode:

<code bash>
apt update
apt install amd64-microcode 
</code>

Reboot.

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===== References =====

https://packages.debian.org/bullseye/amd64-microcode