CPU profiling event seemingly does not work

Describe the bug

I wanted to do some basic profiling on my Scala3 GUI application that runs on the JVM. I ran the sample command from the documentation asprof -e cpu -d 10 -f benchmark.html <PID>. It attaches to the process but as soon as my application is refocused, it just terminates.

Expected vs. actual behavior

I expected to generate the profiling file but the application abruptly terminates.

Reproduction Steps

I start up my application using the mill build system. mill core.run The app uses Java 9's process api to print the PID to stdout. ProcessHandle.current().pid() I attach asprof to the process. asprof -e cpu -d 10 -f benchmark.html 12572

asprof logs:

[WARN] Install JVM debug symbols to improve profile accuracy
Profiling for 10 seconds
Process exited

mill logs:

284] core.run
PID: 12572
[W][16:32:02.231131] pw.conf      | [          conf.c: 1209 pw_conf_load_conf_for_context()] setting config.name to client-rt.conf is deprecated, using client.conf
284/284, 1 FAILED] ./mill core.run 34s
284] [error] core.run Subprocess failed

Additional Information/Context

I experimented a bit but could not find out a lot on what is happening.

• I tested other profiling modes like alloc and nativemem. Those ran fine and generated the html file.
• I tried building the app from source. The behavior was the same as with the prebuilt binaries.
• I tried creating an "über-jar" first using mill core.assembly and attach to that but that did not help either.
• I also ran the profiler on a single file "helloworld" that finished successfully without exiting.

My app only has one foreign dependency which is libgdx. This is the build script:

package build

import mill.*
import scalalib.*

trait CommonModule extends ScalaModule:
    def scalaVersion = "3.5.0"

    def scalacOptions = Seq(
        "-deprecation",
        "-Wsafe-init",
        "-Wshadow:all",
        "-Wunused:imports,params,privates",
    )

object config extends CommonModule
object errors extends CommonModule
object extras extends CommonModule:
    def moduleDeps = Seq(config, errors)

object multimedia extends CommonModule:
    def moduleDeps = Seq(errors, extras)

object core extends CommonModule:
    val gdxVersion = "1.13.5"

    def mvnDeps = Seq(
        mvn"com.badlogicgames.gdx:gdx:$gdxVersion",
        mvn"com.badlogicgames.gdx:gdx-backend-lwjgl3:$gdxVersion",
    )

    def runMvnDeps = Seq(
        mvn"com.badlogicgames.gdx:gdx-platform:$gdxVersion;classifier=natives-desktop"
    )

    def moduleDeps = Seq(multimedia)

Async-profiler version

Latest stable 4.5

Environment details

OS: Artix Linux 6.18.38-4-lts CPU: x86_64 openjdk version "21.0.11" 2026-04-21 OpenJDK Runtime Environment (build 21.0.11+10) OpenJDK 64-Bit Server VM (build 21.0.11+10, mixed mode, sharing) Not running in container