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

[David Daney <ddaney@avtrex.com>]

Thiemo Seufer wrote:
> 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.
OK, good point.

But there is still the leaf function problem.

David Daney.