linux-kernel - Re: [PATCH v2 29/62] objtool: Mark prefix functions

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Message-ID: <tqdgtgqfokasfqqzbn4by6oaphxtwzg75egnq4lj76xjr6eabj@7idrvpy72xux>
Date: Thu, 26 Jun 2025 15:43:45 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, 
	Petr Mladek <pmladek@...e.com>, Miroslav Benes <mbenes@...e.cz>, 
	Joe Lawrence <joe.lawrence@...hat.com>, live-patching@...r.kernel.org, Song Liu <song@...nel.org>, 
	laokz <laokz@...mail.com>, Jiri Kosina <jikos@...nel.org>, 
	Marcos Paulo de Souza <mpdesouza@...e.com>, Weinan Liu <wnliu@...gle.com>, 
	Fazla Mehrab <a.mehrab@...edance.com>, Chen Zhongjin <chenzhongjin@...wei.com>, 
	Puranjay Mohan <puranjay@...nel.org>
Subject: Re: [PATCH v2 29/62] objtool: Mark prefix functions

On Wed, Jun 04, 2025 at 05:04:33PM -0700, Josh Poimboeuf wrote:
> On Mon, May 26, 2025 at 12:43:55PM +0200, Peter Zijlstra wrote:
> > > +++ b/tools/objtool/elf.c
> > > @@ -442,6 +442,11 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
> > >  	elf_hash_add(symbol, &sym->hash, sym->idx);
> > >  	elf_hash_add(symbol_name, &sym->name_hash, str_hash(sym->name));
> > >  
> > > +	if (is_func_sym(sym) && sym->len == 16 &&
> > 
> > Where did that 'sym->len == 16' thing come from? I mean, they are, but
> > the old code didn't assert that.
> > 
> > I would rather objtool issue a warn if not 16, but still consider these
> > as prefix.
> 
> Ok:

Turns out there are kCFI cases with prefixes != 16, so I omitted the
size check altogether.

-- 
Josh