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

[David Daney <ddaney@avtrex.com>]

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.

I would be worried that many stack traces would become less useful.

If this were conditional on -fno-omit-frame-pointer, then I think it 
would be a good idea.

David Daney.