Azure DevOps Ubuntu 24.04 DB Creation for C#

Start by reproducing the Azure DevOps pipeline on the Ubuntu 24.04 image and inspect the reported dotnet --info failure. Trace the C# extraction path through codeql/csharp/tools/autobuild.sh, comparing the installed .NET CLI with what the autobuilder sees. Done means the C# database is created successfully without the exit-134 failure.

Using an Azure DevOps Ubuntu 24.04 image as ubuntu-latest

Downloaded CodeQL command-line toolchain release 2.25.0.

Creating CodeQL DB for 'csharp' in '/home/vsts/work/1/a/codeqldb/csharp' with args: --build-mode none

Receiving the following error message in the pipeline:

========================== Starting Command Output ===========================
/usr/bin/bash --noprofile --norc /home/vsts/work/_temp/c3d589b8-77a0-43fe-b1a2-aefbb9428de0.sh
→ Creating CodeQL DB for 'csharp' in '/home/vsts/work/1/a/codeqldb/csharp' with args: --build-mode none
Initializing database at /home/vsts/work/1/a/codeqldb/csharp.
Running build command: []
Running command in /home/vsts/work/1/s/network: [/home/vsts/work/1/s/codeql/csharp/tools/autobuild.sh]
[2026-03-23 09:09:16] [build-stdout] CodeQL C# autobuilder
[2026-03-23 09:09:16] [build-stdout] Working directory: /home/vsts/work/1/s/network
[2026-03-23 09:09:16] [build-stdout] [001] Extracting C# with build-mode set to 'none'
[2026-03-23 09:09:16] [build-stdout] [001] Finding files in /home/vsts/work/1/s/network...
[2026-03-23 09:09:16] [build-stdout] [001] Found 766 files in /home/vsts/work/1/s/network
[2026-03-23 09:09:16] [build-stdout] [001] Found 766 small non-binary files in /home/vsts/work/1/s/network.
[2026-03-23 09:09:16] [build-stdout] [001] Found 426 source files in /home/vsts/work/1/s/network.
[2026-03-23 09:09:16] [build-stdout] [001] Found 0 global.json files in /home/vsts/work/1/s/network.
[2026-03-23 09:09:16] [build-stdout] [001] No Dependabot proxy credentials are configured.
[2026-03-23 09:09:16] [build-stdout] [001] Using .NET CLI executable: 'dotnet'
[2026-03-23 09:09:16] [build-stdout] [001] Running 'dotnet --info'
[2026-03-23 09:09:19] [build-stderr] [001] Error: Missing dotnet CLI
[2026-03-23 09:09:19] [build-stderr] Unhandled exception. System.Exception: dotnet --info failed with exit code 139.
[2026-03-23 09:09:19] [build-stderr] at Semmle.Extraction.CSharp.DependencyFetching.DotNet.Info()
[2026-03-23 09:09:19] [build-stderr] at Semmle.Extraction.CSharp.DependencyFetching.DotNet..ctor(IDotNetCliInvoker dotnetCliInvoker, ILogger logger, Boolean runDotnetInfo, TemporaryDirectory tempWorkingDirectory)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Extraction.CSharp.DependencyFetching.DotNet..ctor(ILogger logger, String dotNetPath, TemporaryDirectory tempWorkingDirectory, DependabotProxy dependabotProxy)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Extraction.CSharp.DependencyFetching.DotNet.Make(ILogger logger, String dotNetPath, TemporaryDirectory tempWorkingDirectory, DependabotProxy dependabotProxy)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Extraction.CSharp.DependencyFetching.DependencyManager..ctor(String srcDir, ILogger logger)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Extraction.CSharp.Standalone.Extractor.Run(Options options)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Extraction.CSharp.Standalone.Program.Main(String[] args)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Autobuild.CSharp.StandaloneBuildRule.<>c.b__0_1(IBuildActions _)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Util.BuildScript.ReturnBuildCommand.Run(IBuildActions actions, Action2 startCallback, Action3 exitCallBack, BuildOutputHandler onOutput, BuildOutputHandler onError)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Util.BuildScript.BindBuildScript.Run(IBuildActions actions, Action2 startCallback, Action3 exitCallBack, BuildOutputHandler onOutput, BuildOutputHandler onError)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Util.BuildScript.BindBuildScript.Run(IBuildActions actions, Action2 startCallback, Action3 exitCallBack, BuildOutputHandler onOutput, BuildOutputHandler onError)
[2026-03-23 09:09:19] [build-stderr] at Semmle.Autobuild.Shared.Autobuilder`1.AttemptBuild()
[2026-03-23 09:09:19] [build-stderr] at Semmle.Autobuild.CSharp.Program.Main()
[2026-03-23 09:09:21] [build-stderr] Aborted (core dumped)
[2026-03-23 09:09:21] [ERROR] Spawned process exited abnormally (code 134; tried to run: [/home/vsts/work/1/s/codeql/csharp/tools/autobuild.sh])
A fatal error occurred: Exit status 134 from command: [/home/vsts/work/1/s/codeql/csharp/tools/autobuild.sh]

##[error]Bash exited with code '2'.
Finishing: codeql: database-build-csharp

We have already installed dotnet on the image, I can't work out why our pipelines are failing?