Ok, tried it properly with a new class which inherits DEVICE::SerialPort and the direct way above. Both have the same effect:
*** Error in `/usr/bin/perl': corrupted double-linked list: 0x00000000
+0173d840 ***
or
Segmentation fault (core dumped)
The error messages differ on the crashes. Seems the garbage collection still wants to clean up something and messes it up.
Found
this. Sadly i don't understand it and don't know if this may be of any help.
Tomorrow i'll try your second suggestion. Thx alot so far.