The spin buttons in the memory window are defined with an upper bound that does not allow access to the full 64-bit address range. When the memory window is opened with a base address that is above the upper bound for the spin button, memory at the address indicated by the upper bound is accessed, which often causes a ptrace exception.
This also applies to the disassembly window.
Need to set upper bound based on task's ISA
That was my suggestion indeed, and is currently being implemented. An extension of this will be that once segment selection is implemented, the bounds should be set based on the segment boundaries. Selecting the default segment of the entire addressable space would result in the default 0 through end-of-address-space boundaries being set, allowing full access to any arbitrary address on the platform.
2007-06-20 Kris Van Hees <kris.van.hees@oracle.com> * memory/MemoryWindow.java (setTask, resetTask): Set the valid range of the fromSpin and toSpin buttons from 0 to the highest address for the task's ISA (2^wordsize - 1). * disassembler/DisassemblyWindow.java (setTask, resetTask): Set the valid range of the fromSpin and toSpin buttons from 0 to the highest address for the task's ISA (2^wordsize - 1).