Swap misidentified due to trailing newline in file

[linuxdaemon]

What happened:

While deploying NFD 0.16.0 on a k8s 1.30.2 node (Ubuntu 22.04), I noticed it assigned memory-swap=true despite swap not being enabled on this system.

What you expected to happen:

I expected NFD to recognize that no swap device is registered

How to reproduce it (as minimally and precisely as possible):

As far as I can tell, the issue is that /proc/swaps ends in a newline character \n, while the testdata has no such trailing newline. So any system which has /proc/swaps with a trailing newline will be misidentified.

Anything else we need to know?:

This system is a VM which was initially created with swap which was then removed as part of the k8s provisioning process. /proc/swaps contains only the header line and a single \n character now.

Environment:

• Kubernetes version (use kubectl version): v1.30.2
• Cloud provider or hardware configuration: VM on local proxmox instance
• OS (e.g: cat /etc/os-release): Ubuntu 22.04
• Kernel (e.g. uname -a): 5.15.0-113-generic
• Install tools:
  • Cluster created with kubeadm version: &version.Info{Major:"1", Minor:"30", GitVersion:"v1.30.2", GitCommit:"39683505b630ff2121012f3c5b16215a1449d5ed", GitTreeState:"clean", BuildDate:"2024-06-11T20:27:59Z", GoVersion:"go1.22.4", Compiler:"gc", Platform:"linux/amd64"}
  • Helm: Terraform provider version 2.14.0

I believe the fix is as simple as ignoring empty lines when checking number of lines in the file, though I won't have time to open a PR until next weekend at the earliest, so someone else is welcome to take this on as well.

[marquiz]

Thanks @linuxdaemon for reporting this issue.

ping @kannon92 @TessaIO

[TessaIO]

I will look into this ASAP!

[TessaIO]

/assign