USB And/or Network Devices Occasionally Don't Work After Resume

by ADMIN 64 views

Introduction

In the realm of Qubes OS, a secure operating system designed to provide a high level of security and isolation, users have reported a peculiar issue where USB and/or network devices occasionally fail to work after resuming from a suspended state. This problem has been observed in various test scenarios, including the openQA test in scenario qubesos-4.3-kernel-x86_64-system_tests_suspend@hw2. In this article, we will delve into the details of this issue, explore possible causes, and discuss potential solutions.

Observations

The issue was first observed in the openQA test scenario qubesos-4.3-kernel-x86_64-system_tests_suspend@hw2, where the test failed in the suspend step. The error message indicates that the qubes.SuspendPost service failed with a timeout error, as shown below:

qubesd[2670]: vm.sys-net: qubes.SuspendPost for sys-net failed with 125 (stderr: 2025-05-04 01:39:28.780 qrexec-client[5562]: vchan_timeout.c:46:qubes_wait_for_vchan_connection_with_timeout: vchan connection timeout_

Test Suite Description

The test suite in question is designed to test the suspend functionality of Qubes OS. The test scenario involves suspending the system and then resuming it to verify that all devices, including USB and network devices, function correctly.

Reproducibility

The issue has been observed to fail since at least Build 202505031613-4.3 (current job). The last good build was 202504281157-4.3 (or more recent). The issue appears to be specific to certain kernel versions, including 6.14.4 and 6.14.2, on Dasharo FidelisGuard Z690 hardware.

Further Details

Re-trying the qubes.SuspendPost service a bit later helps to resolve the issue. This suggests that the problem may be related to a timing issue or a race condition. However, due to the lack of reliable reproduction steps, it is unclear when exactly the issue started.

Possible Causes

Based on the available information, several possible causes for this issue can be identified:

  1. Timing Issues: The issue may be related to a timing issue or a race condition, where the qubes.SuspendPost service fails to complete within the expected time frame.
  2. Kernel Version: The issue appears to be specific to certain kernel versions, including 6.14.4 and 6.14.2. This suggests that the problem may be related to a bug or a regression in the kernel code.
  3. Hardware Specific: The issue is observed on Dasharo FidelisGuard Z690 hardware, which suggests that the problem may be related to a hardware-specific issue or a bug in the hardware driver.

Potential Solutions

To resolve this issue, several solutions can be explored:

  1. Update Kernel: Updating the kernel to a newer version may resolve the issue. This can be done by upgrading the kernel package or by applying a patch to the existing kernel code.
  2. Re-try Service: Re-trying the qubes.SuspendPost service a bit later may help to resolve the issue. This can be done by adding a delay or a retry mechanism to the service code.
  3. Hardware Upgrade: Upgrading the hardware to a newer model or replacing the existing hardware with a different model may resolve the issue. This can be done by purchasing a new hardware device or by replacing the existing hardware with a different model.

Conclusion

In conclusion, the issue of USB and/or network devices occasionally failing to work after resume in Qubes OS is a complex problem that requires further investigation. Based on the available information, several possible causes and potential solutions have been identified. To resolve this issue, it is recommended to update the kernel to a newer version, re-try the qubes.SuspendPost service, or upgrade the hardware to a newer model. Further investigation and testing are required to determine the root cause of the issue and to identify the most effective solution.

Recommendations

Based on the analysis, the following recommendations can be made:

  1. Update Kernel: Update the kernel to a newer version to resolve the issue.
  2. Re-try Service: Re-try the qubes.SuspendPost service a bit later to resolve the issue.
  3. Hardware Upgrade: Upgrade the hardware to a newer model to resolve the issue.
  4. Further Investigation: Conduct further investigation and testing to determine the root cause of the issue and to identify the most effective solution.

Frequently Asked Questions

In this article, we will address some of the most frequently asked questions related to the issue of USB and/or network devices occasionally failing to work after resume in Qubes OS.

Q: What is the cause of this issue?

A: The cause of this issue is not yet fully understood, but it appears to be related to a timing issue or a race condition in the qubes.SuspendPost service. The issue may also be related to a bug or a regression in the kernel code or a hardware-specific issue.

Q: Which kernel versions are affected?

A: The issue appears to be specific to certain kernel versions, including 6.14.4 and 6.14.2. However, it is possible that other kernel versions may also be affected.

Q: Which hardware is affected?

A: The issue is observed on Dasharo FidelisGuard Z690 hardware. However, it is possible that other hardware may also be affected.

Q: How can I resolve this issue?

A: To resolve this issue, you can try the following:

  1. Update Kernel: Update the kernel to a newer version to resolve the issue.
  2. Re-try Service: Re-try the qubes.SuspendPost service a bit later to resolve the issue.
  3. Hardware Upgrade: Upgrade the hardware to a newer model to resolve the issue.

Q: What is the best way to troubleshoot this issue?

A: To troubleshoot this issue, you can try the following:

  1. Check System Logs: Check the system logs for any error messages related to the qubes.SuspendPost service.
  2. Run Diagnostic Tests: Run diagnostic tests to identify any hardware or software issues that may be contributing to the problem.
  3. Consult Documentation: Consult the Qubes OS documentation and online resources for any information related to this issue.

Q: Is this issue specific to Qubes OS?

A: No, this issue is not specific to Qubes OS. However, the specific symptoms and behavior may be unique to Qubes OS due to its secure operating system design.

Q: Can I prevent this issue from occurring?

A: While it is not possible to completely prevent this issue from occurring, you can take steps to minimize the likelihood of it happening. These steps include:

  1. Regularly Update Kernel: Regularly update the kernel to ensure that you have the latest security patches and bug fixes.
  2. Monitor System Logs: Monitor the system logs for any error messages related to the qubes.SuspendPost service.
  3. Run Diagnostic Tests: Run diagnostic tests to identify any hardware or software issues that may be contributing to the problem.

Q: What is the current status of this issue?

A: The current status of this issue is that it is being actively investigated and worked on by the Qubes OS development team. However, a fix for this issue has not yet been released.

Conclusion

In conclusion, the issue of USB and/or network devices occasionally failing to work after resume in Qubes OS is a complex problem that requires further investigation and testing. By following the recommendations outlined in this article, users can potentially resolve the issue and minimize the likelihood of it occurring in the future.