Subject: Re: [PATCH v2] ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function

From: Ingo Molnar <[email-masked]>
Date: Fri, 27 May 2022 12:04:14 +0200

* Steven Rostedt <[email-masked]> wrote:

> On Thu, 26 May 2022 04:50:17 +0200
> Ingo Molnar <[email-masked]> wrote:
> 
> 
> > > The real fix would be to fix kallsyms to not show address of weak
> > > functions as the function before it. But that would require adding code in
> > > the build to add function size to kallsyms so that it can know when the
> > > function ends instead of just using the start of the next known symbol.  
> > 
> > Yeah, so I actually have a (prototype...) objtool based kallsyms 
> > implementation in the (way too large) fast-headers tree that is both faster 
> > & allows such details in principle:
> 
> Nice.
> 
> Will this work for other architectures too?

For those which implement objtool, it certainly should: as we parse through 
each object file during the build, generating kallsyms data structures is 
relatively straightforward.

Objtool availability is a big gating condition though. :-/

[ ... and still Acked-by on -v4 too. ]

Thanks,

	Ingo