Re: [PATCH modules-next v10 00/13] kallsyms: reliable symbol->address lookup with /proc/kallmodsyms

From: Petr Mladek <pmladek@suse.com>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
	Nick Alcock <nick.alcock@oracle.com>,
	masahiroy@kernel.org, linux-modules@vger.kernel.org,
	linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org,
	arnd@arndb.de, akpm@linux-foundation.org, eugene.loh@oracle.com,
	kris.van.hees@oracle.com, live-patching@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH modules-next v10 00/13] kallsyms: reliable symbol->address lookup with /proc/kallmodsyms
Date: Tue, 25 Apr 2023 10:27:42 +0200	[thread overview]
Message-ID: <ZEeO_rWL4bDh5vui@alley> (raw)
In-Reply-To: <ZEbc20oRFR0f8Qj6@bombadil.infradead.org>

On Mon 2023-04-24 12:47:39, Luis Chamberlain wrote:
> On Fri, Apr 07, 2023 at 04:21:18PM -0700, Josh Poimboeuf wrote:
> > Anyway, I was nodding along with the above cover letter until I got to
> > the third paragraph.
> > 
> > A "built-in kernel module" is not actually a module, as it's built in to
> > vmlinux.  I suspect the point is that if you rebuild with a different
> > config, it might become a module.  But many other changes could also
> > occur with a changed config, including changed inlining decisions and
> > GCC IPA optimization function renaming, in which case the symbol might
> > no longer exist with the new config.
> 
> Yes it does not matter, for his tooling effort it was just to be able
> to map a possible module to a symbol so tooling can display this to
> disambiguate.

Note that the same symbol name might be used many times even within
one module. The module might be linked from more .o files. And
more .o files might have a local symbol with the same name.

I think that the best solution is to associate the symbol with
the file name and line. These is very useful information in general.

Best Regards,
Petr