Problem solved, but not fully explained
After thorough investigation, I've stated that the "nm" program
generates segmentation fault, when doing
"nm -n .tmp_vmlinux1" during the compilation of the kernel.
I ve stated, that this program is part of binutils package, so I've
force reinstallation by
" apt-get install binutils --reinstall", and now everything works correctly.
It is still unclear however what has caused the observed improper work
of the "nm" program.
Was it a file corruption on the disk, or I've installed a damaged
I'm afraid it is not possible to check it now.
Anyway the problem is solved.
Sorry for confusion & Regards,