linux-kernel - Re: [RFC][PATCH 1/3] objtool: Clean up elf

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Message-ID: <20200615184411.GH2531@hirez.programming.kicks-ass.net>
Date:   Mon, 15 Jun 2020 20:44:11 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Matt Helsley <mhelsley@...are.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        linux-kernel@...r.kernel.org, x86@...nel.org, dvyukov@...gle.com,
        elver@...gle.com, andreyknvl@...gle.com, mark.rutland@....com,
        rostedt@...dmis.org, jthierry@...hat.com, mbenes@...e.cz
Subject: Re: [RFC][PATCH 1/3] objtool: Clean up elf_write() condition

On Mon, Jun 15, 2020 at 11:34:48AM -0700, Matt Helsley wrote:
> On Fri, Jun 12, 2020 at 04:30:35PM +0200, Peter Zijlstra wrote:
> > With there being multiple ways to change the ELF data, let's more
> > concisely track modification.
> > 
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> 
> Would it make sense to set the relocation section's "changed" flag in
> addition to the elf struct's changed flag in elf_rebuild_reloc_section()?
> 
> Right now I think the code is  assuming that it's a newly created section
> but it would be more defensive to set it during a rebuild too I think.

Indeed, currently the code assumes (and this is so) elf_rebuild_rela_sections()
is only called on an elf_create_reloc_section() result and thus setting
->changed is superfluous.

But sure, I can certainly set them there too.