NullPointerException and IllegalThreadStateException when repeatedly connecting

[fantostisch]

General information

1. Android Version: 11
2. Android Vendor/Custom ROM: OnePlus OxygenOS
3. Device: OnePlus 9 Pro
4. Version of the app (version number/play store version/self-built):
   Bug seems to occur in F-Droid version v0.7.37, but not in v.0.7.29. After testing different versions, it seems that the bug is introduced in 3a674d3

Description of the issue

When repeatedly and quickly pressing an OpenVPN shortcut and immediately pressing the back button on the device to close the OpenVPN log, OpenVPN crashes.
The same crashes occur when repeatedly pressing the connect/disconnect toggle in the latest version of the eduVPN Android app.

Log

Different crashes occur:

java.lang.NullPointerException: Attempt to invoke virtual method 'void java.lang.Thread.start()' on a null object reference
	at de.blinkt.openvpn.core.OpenVPNService.startOpenVPN(OpenVPNService.java:638)
	at de.blinkt.openvpn.core.OpenVPNService.lambda$onStartCommand$1$de-blinkt-openvpn-core-OpenVPNService(OpenVPNService.java:528)
	at de.blinkt.openvpn.core.OpenVPNService$$ExternalSyntheticLambda0.run(Unknown Source:6)
	at java.lang.Thread.run(Thread.java:923)

java.lang.IllegalThreadStateException
	at java.lang.Thread.start(Thread.java:872)
	at de.blinkt.openvpn.core.OpenVPNService.startOpenVPN(OpenVPNService.java:638)
	at de.blinkt.openvpn.core.OpenVPNService.lambda$onStartCommand$1$de-blinkt-openvpn-core-OpenVPNService(OpenVPNService.java:528)
	at de.blinkt.openvpn.core.OpenVPNService$$ExternalSyntheticLambda0.run(Unknown Source:6)
	at java.lang.Thread.run(Thread.java:923)

java.lang.NullPointerException: Attempt to invoke virtual method 'void java.lang.Thread.start()' on a null object reference
	at de.blinkt.openvpn.core.OpenVPNService.startOpenVPN(OpenVPNService.java:638)
	at de.blinkt.openvpn.core.OpenVPNService.lambda$onStartCommand$1$de-blinkt-openvpn-core-OpenVPNService(OpenVPNService.java:528)
	at de.blinkt.openvpn.core.OpenVPNService$$ExternalSyntheticLambda0.run(Unknown Source:6)
	at java.lang.Thread.run(Thread.java:923)

java.lang.NullPointerException: Attempt to invoke virtual method 'void de.blinkt.openvpn.core.DeviceStateReceiver.networkStateChange(android.content.Context)' on a null object reference
	at de.blinkt.openvpn.core.OpenVPNService.registerDeviceStateReceiver(OpenVPNService.java:451)
	at de.blinkt.openvpn.core.OpenVPNService.lambda$startOpenVPN$2$de-blinkt-openvpn-core-OpenVPNService(OpenVPNService.java:659)
	at de.blinkt.openvpn.core.OpenVPNService$$ExternalSyntheticLambda1.run(Unknown Source:4)
	at android.os.Handler.handleCallback(Handler.java:938)
	at android.os.Handler.dispatchMessage(Handler.java:99)
	at android.os.Looper.loop(Looper.java:233)
	at android.app.ActivityThread.main(ActivityThread.java:8035)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:631)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:978)

[fantostisch]

Video showing the error:

recording.mp4

[fantostisch]

A normal user might not do such actions to trigger this error, but the IllegalThreadStateException and NullPointerException seem to show up in the crashes in the Play Store of the eduVPN app, so I think there should be other ways to trigger the issue.

[schwabe]

Are you sure those stacktraces are from 0.7.37? I am looking at OpenVPNService.java:638 but that is only a closing bracket of a function and the OpenVPNService.java:659 is just a synchronized (mProcessLock) and OpenVPNService.java:451 which the stacktrace puts into registerDeviceStateReceiver is actually in unregisterDeviceStateReceiver