Hi there, In my continuing saga (which some are becoming familiar with) to get UML 2.6.x working at all I have been given access to another machine to develop on and my old machine is going to disappear. This machine is Debian Sarge with gcc 3.3.5 on an AMD64 with 32 bit userspace although 64 bit compiles can also occur. I am doing all my UML builds with ARCH=um SUBARCH=i386 at this point in time. The problem is that my bootup dies very early on and this is the total output: Checking for /proc/mm...not found Checking PROT_EXEC mmap in /tmp...OK tracing thread pid = 20981 OP_FORK failed to attach pid I suspect that this is something to do with my mixed 32/64 bit environment but I am not sure... Can anybody shed some light on this? BTW I have also written a patch which I think is worth submitting into the kernel tree as it gives better debugging of error messages in arch/um/kernel/tt/tracer.c for where my process is dying. When I run with my patch it shows that it is dying on the PTRACE_ATTACH with an error EPERM but I can run other processes etc like gdb which attach to processes. Any help would be greatly appreciated. Ian