Re: [PATCH] dump_stack() based on prologue code analysis

[Thiemo Seufer <ths@networkno.de>]

David Daney wrote:
> Atsushi Nemoto wrote:
> >Instead of dump all possible address in the stack, unwind the stack
> >frame based on prologue code analysis, as like as get_chan() does.
> >While the code analysis might fail for some reason, there is a new
> >kernel option "raw_show_trace" to disable this feature.
> >
> >Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
> 
> Let me start by saying I have not analyzed how all this code works, but 
> I have done something similar in user space.
> 
> Since the kernel ABI does not use gp, many functions may not have a 
> prolog (especially when compiled with newer versions of GCC).  In the 
> user space case, most leaf functions have no prolog.  For the kernel I 
> would imagine that many non-leaf functions (simple non-leaf functions 
> that do only a tail call) would also not have a prolog.

Non-leaves have to save/restore $31 somewhere, so there should be a
prologue.


Thiemo