linux-kernel - Re: [PATCH] objtool: Fix GCC 8 cold function processing without -freorder-functions

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Message-ID: <3a9a1cfa-4357-264e-3333-220a7f83a51d@oracle.com>
Date:   Tue, 26 Jun 2018 19:31:18 +0100
From:   Allan Xavier <allan.x.xavier@...cle.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Josh Poimboeuf <jpoimboe@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] objtool: Fix GCC 8 cold function processing without
 -freorder-functions

Hi Peter,

On 26/06/18 17:43, Peter Zijlstra wrote:
> On Tue, Jun 26, 2018 at 05:20:45PM +0100, Allan Xavier wrote:
>> 0000000000000500 g     F .text  0000000000000034 nmi_panic
>> 0000000000000528 l     F .text  000000000000000c nmi_panic.cold.7
>>
>> This doesn't happen with -freorder-functions in the first example as the
>> symbols don't overlap. 
> 
> Urgh and I don't suppose we can 'fix' the overlap in read_symbols() ?
> 

It should be fixable in read_symbols too if you don't mind sym->len not being
the same as sym->st_size in the ELF.

Is there a particular concern you're trying to address by having the logic there
instead?

Will have a look into reworking the patch in any case.

Thanks,
Allan