Make sure no other windows are open for the qube

Oct 13, 2025 by wbrum.org 52 views

qubes-app-shutdown-idle incorrectly monitors idleness and shuts down prematurely

Qubes OS is a highly secure operating system designed to provide a safe and private computing environment. One of its key features is the ability to shut down individual qubes when they are idle for a specified period of time. However, a recent issue has been discovered in the qubes-app-shutdown-idle functionality, which incorrectly monitors idleness and shuts down qubes prematurely. In this article, we will delve into the details of this issue, its causes, and potential solutions.

The problem arises when an application, such as Zoom, quickly maps and unmaps windows. This behavior triggers the idleness monitor to shut down the qube, even though it has not been idle for the specified period of time. For example, if you enable shut down when idle for more than 15 minutes and run Zoom from the launcher, the qube will immediately shut down. This is because the idleness monitor assumes that all state changes go from idle->non-idle->idle, but in reality, it is possible for state changes to happen without the idle state changing.

To reproduce this issue, follow these steps:

Install Zoom into a qube: Install the Zoom application into a qube and enable shut down when idle for more than 15 minutes.
Make sure no other windows are open for the qube: Ensure that no other windows are open for the qube, as this will prevent the idleness monitor from shutting everything down.
Run Zoom from the launcher: Run Zoom from the launcher, and observe the behavior of the qube.

The expected behavior is that Zoom will open, and the qube will remain running. However, due to the issue with the idleness monitor, the qube will immediately shut down.

The actual behavior is that the qube will shut down immediately, even though it has not been idle for the specified period of time.

The issue lies in the monitor_idleness function in qubesidle/idleness_monitor.py. This function assumes that all state changes go from idle->non-idle->idle, but in reality, it is possible for state changes to happen without the idle state changing. This can lead to a situation where the function returns, shutting down the qube, with idleness of much less than 15 minutes.

There are several possible causes of this issue:

Race conditions: The monitor_idleness function may be subject to race conditions, where multiple threads or processes access the same resource simultaneously, leading to incorrect behavior.
Incorrect assumptions: The function may be making incorrect assumptions about the behavior of the qube and the applications running on it.

To resolve this issue, several potential solutions can be explored:

Modify the monitor_idleness function: The function can be modified to check that it is both idle and has been 15 minutes since the last time it was idle, rather than assuming that two consecutive idle checks mean the system is idle.
Implement a more robust idleness monitoring mechanism: A more robust idleness monitoring mechanism can be implemented, which takes into account the behavior of multiple applications and threads.
Add additional logging and debugging: Additional logging and debugging can be added to the monitor_idleness function to help identify the root cause of the issue.

In conclusion, the qubes-app-shutdown-idle functionality in Qubes OS has a critical issue that causes it to incorrectly monitor idleness and shut down qubes prematurely. This issue is caused by the monitor_idleness function making incorrect assumptions about the behavior of the qube and the applications running on it. To resolve this issue, several potential solutions can be explored, including modifying the monitor_idleness function, implementing a more robust idleness monitoring mechanism, and adding additional logging and debugging.
Qubes-app-shutdown-idle Incorrectly Monitors Idleness and Shuts Down Prematurely: Q&A

In our previous article, we discussed the issue with the qubes-app-shutdown-idle functionality in Qubes OS, which incorrectly monitors idleness and shuts down qubes prematurely. In this article, we will provide a Q&A section to help answer some of the most frequently asked questions about this issue.

A: The qubes-app-shutdown-idle functionality is a feature in Qubes OS that allows you to shut down individual qubes when they are idle for a specified period of time.

A: The issue is that the functionality incorrectly monitors idleness and shuts down qubes prematurely. This is caused by the monitor_idleness function making incorrect assumptions about the behavior of the qube and the applications running on it.

A: The symptoms of this issue include the qube shutting down immediately, even though it has not been idle for the specified period of time. This can happen when an application, such as Zoom, quickly maps and unmaps windows.

A: To reproduce this issue, follow these steps:

Install Zoom into a qube and enable shut down when idle for more than 15 minutes.
Make sure no other windows are open for the qube.
Run Zoom from the launcher.

A: The possible causes of this issue include:

Race conditions: The monitor_idleness function may be subject to race conditions, where multiple threads or processes access the same resource simultaneously, leading to incorrect behavior.
Incorrect assumptions: The function may be making incorrect assumptions about the behavior of the qube and the applications running on it.

A: To resolve this issue, several potential solutions can be explored:

Modify the monitor_idleness function: The function can be modified to check that it is both idle and has been 15 minutes since the last time it was idle, rather than assuming that two consecutive idle checks mean the system is idle.
Implement a more robust idleness monitoring mechanism: A more robust idleness monitoring mechanism can be implemented, which takes into account the behavior of multiple applications and threads.
Add additional logging and debugging: Additional logging and debugging can be added to the monitor_idleness function to help identify the root cause of the issue.

A: No, this issue is not specific to Qubes OS. Similar issues can occur in other operating systems that use similar idleness monitoring mechanisms.

A: Yes, you can prevent this issue from occurring by disabling the shut down when idle feature or by modifying the monitor_idleness function to use a more robust idleness monitoring mechanism.

In conclusion, the qubes-app-shutdown-idle functionality in Qubes OS has a critical issue that causes it to incorrectly monitor idleness and shut down qubes prematurely. By understanding the symptoms, possible causes, and potential solutions to this issue, you can take steps to prevent it from occurring and ensure that your qubes run smoothly and efficiently.