[RFC] Support for KASLR

[Frank Ch. Eigler]

Hi, Torsten -

> [...]
> I’ve a kernel with the configuration option CONFIG_RANDOMIZE_BASE
> set. The backtrace fails for the kernel. The patch tries to address
> this issue. [...]
> _stext.

It would surprise for systemtap to need this sort of thing now.  KASLR
is a years-old technique, and CONFIG_RANDOMIZE_BASE has been default for
most of that time.  We routinely relocate our internal kernel
symbol/unwind info with respect to the same _stext symbol.  I wonder
what is going on.

- FChE