jcmd, windows x64: cannot list other processes

On my local laptop, jcmd does not list any other processes but itself. I can attach just fine (via pid), just the listing fails.

The setup is very simple.

On my local machine, I build jdk-hs from the current tip. Then I run a simple java HelloWorld, without any options given. The program just waits on a keystroke.

$ ../../openjdk/jdk-hs/output-fastdbg/images/jdk/bin/java HelloWorld

Then I start jcmd from the same image with no special options.

$ ./images/jdk/bin/jcmd
248472 jdk.jcmd/sun.tools.jcmd.JCmd

And I only see the jcmd process itself.

Note that in this example I run from cygwin shells, but the same error happens when running from cmd.exe.

Also note that I also have other java processes running on the same box, eg an Eclipse instance using openjdk9. It does not show up in the jcmd process listing either.

I can attach to my HelloWorld process via pid:

$ ./images/jdk/bin/jcmd 248204 help
248204:
The following commands are available:
VM.log
VM.native_memory
.....

But unsurprisingly not via name:

$ ./images/jdk/bin/jcmd HelloWorld help
Could not find any processes matching : 'HelloWorld'

I took some minutes to check if the issue is easy to fix: - I set a native breakpoint at Java_sun_tools_attach_AttachProviderImpl_enumProcesses(), but never hit it. I did not have time to investigate further.

My machine runs Windows 10.