Process.WaitForExit() deadlock when running multiple processes on linux with .net7

[kirnosenko]

Description

Running multiple processes concurrently using System.Diagnostics.Process causes a deadlock on linux with .net7. I checked this, but I believe it is something else.

Reproduction Steps

A simple example to reproduce deadlock is here.

Expected behavior

no deadlock

Actual behavior

deadlock

Regression?

No response

Known Workarounds

No response

Configuration

.net7 on x64 alpine linux container

Other information

I tested it in different environments:
.net6 + windows = fine
.net6 + linux = fine
.net7 + windows = fine
.net7 + linux = deadlock

[ghost]

Tagging subscribers to this area: @dotnet/area-system-diagnostics-process
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Running multiple processes concurrently using System.Diagnostics.Process causes a deadlock on linux with .net7. I checked this, but I believe it is something else.

Reproduction Steps

A simple example to reproduce deadlock is here.

Expected behavior

no deadlock

Actual behavior

deadlock

Regression?

No response

Known Workarounds

No response

Configuration

.net7 on x64 alpine linux container

Other information

I tested it in different environments:
.net6 + windows = fine
.net6 + linux = fine
.net7 + windows = fine
.net7 + linux = deadlock

Author:	kirnosenko
Assignees:	-
Labels:	area-System.Diagnostics.Process
Milestone:	-

[adamsitnik]

@tmds is there any chance you could take a look?

[tmds]

@kirnosenko you've only observed this issue in a container, right?

You can work around it by changing the entrypoint to something like:

ENTRYPOINT ["/bin/sh", "-c", "dotnet <your_assembly>.dll"]

#79817 fixes this and is backported for an upcoming 7.0 patch release.

[kirnosenko]

@tmds yes I run it in container, unfortunately your suggestion makes no any difference, still has a deadlock.

[tmds]

unfortunately your suggestion makes no any difference, still has a deadlock.

Ah, I thought it would be enough to make the .NET process have another pid than 1, but that's not true.

If you add the --init flag to the docker run command (which adds an init process as pid 1), the deadlock disappears.

#79817 fixes this issue.

[adamsitnik]

@tmds thank you for your help!