strange iphone os4.0 error while quitting application

I have updated to xcod开发者_JAVA技巧e 3.2.3 iphone os sdk 4.0. now when application enters in background state and when i double tap home screen to quit the bg running app. I receive Kill in gdb. Does some one knows about it ?

If your quit app app it's no longer running, so GDB get KILL signal, nothing wrong..