[.NET8 + ARM64] Build no longer responds to SIGTERM and gets the Ubuntu service manager in trouble

[DierkDroth]

Description

I'm building my ARM64 binary by either of both commands below (the reported issue exists on both builds):

dotnet publish -c Release -r linux-arm64 -p:PublishSingleFile=true -p:SelfContained=true -p:UseNativeAOTCompiler=true MyProject.csproj
dotnet publish -c Release -r linux-arm64 -p:PublishSingleFile=true -p:SelfContained=true -p:PublishReadyToRun=true MyProject.csproj

The .NET 7 binary responds well to the Ubuntu service manager command for stopping the server

service MyService stop

With .NET 8 this no longer works well: the Ubuntu service manager sends out SIGTERM, which is not respected by the .NET 8 binary but keeps the service running. This triggers a timeout logic on the Ubuntu service manager and makes it sending out SIGKILL to finally kill the service. Obviously not the preferred handling...

How could the .NET 7 signal handling be restored?

Reproduction Steps

Please see above

Expected behavior

.NET8 build should work as .NET 7 build

Actual behavior

.NET8 build does not work as .NET 7 build

Regression?

yes

Known Workarounds

none

Configuration

No response

Other information

No response

[jkotas]

I have tried to run long-running build in one terminal and send kill <PID of dotnet build command used to launch the build> in a second terminal. (kill sends SIGTERM by default.) The build process responded to the kill command properly.

Could you please share more detailed steps for reproducing the issue?

This issue has been marked needs-author-action and may be missing some important information.

[DierkDroth]

@jkotas thanks for getting back to me.

To clarify: this is not the build process which would not respond to SIGTERM, it's the resulting binary which is run on an Ubuntu server as a service which does no longer respond to SIGTERM but only to SIGKILL.

Here is a screenshot of

• the service running and
• as I tried to stop it by service unusual stop. You can see that the Ubuntu service manager tries to shutdown the service by SIGTERM

And here is the screenshot which shows that the Ubuntu service manager timed out on SIGTERM but does a hard kill using SIGKILL -> bad

Hope this makes it clearer. Please let me know if your needed anything else. Thanks

[jkotas]

Ah ok. It means that some code in your service registered for SIGTERM signal, but the signal handler is not returning. We need to find out the offending code. It can be any library used by your service. Are you able to take a crash dump or attach debugger to the service when it is not responding to the SIGTERM signal? You should be able to find the blocked signal handler by looking at the stack traces of all threads at that point.

Here is a small console app that demonstrates the problem. It won't respond to SIGTERM just like your service because the SIGTERM signal handler is infinite loop.

using System.Runtime.InteropServices;

PosixSignalRegistration.Create(PosixSignal.SIGTERM, (context) => { for(;;) Console.WriteLine("Trying to shutdown"); });

for (; ; ) Console.WriteLine("Running");

This issue has been marked needs-author-action and may be missing some important information.

[jkotas]

Is your service built using Microsoft.Extensions.Hosting?

Microsoft.Extensions.Hosting registers SIGTERM signal handler that calls ApplicationLifetime.StopApplication that needs to complete for the application to respond to SIGTERM.

[DierkDroth]

Unfortunately I can't attach any debugger.

Here is the list of NuGets packages which are needed to build the binary. May be that helps