linux-kernel - Re: [RFC v5 04/57] objtool: check: Ignore empty alternative groups

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Message-ID: <35333a67-cf5b-450f-0f9b-c75ae1f9be8b@redhat.com>
Date:   Thu, 23 Jan 2020 11:45:42 +0000
From:   Julien Thierry <jthierry@...hat.com>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        peterz@...radead.org, raphael.gault@....com,
        catalin.marinas@....com, will@...nel.org
Subject: Re: [RFC v5 04/57] objtool: check: Ignore empty alternative groups



On 1/21/20 4:30 PM, Josh Poimboeuf wrote:
> On Thu, Jan 09, 2020 at 04:02:07PM +0000, Julien Thierry wrote:
>> Atlernative section can contain entries for alternatives with no
>> instructions. Objtool will currently crash when handling such an entry.
>>
>> Just skip that entry, but still give a warning to discourage useless
>> entries.
>>
>> Signed-off-by: Julien Thierry <jthierry@...hat.com>
>> ---
>>   tools/objtool/check.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
>> index 5968e6f08891..27e5380e0e0b 100644
>> --- a/tools/objtool/check.c
>> +++ b/tools/objtool/check.c
>> @@ -866,6 +866,13 @@ static int add_special_section_alts(struct objtool_file *file)
>>   		}
>>   
>>   		if (special_alt->group) {
>> +			if (!special_alt->orig_len) {
>> +				WARN("empty alternative entry at %s+0x%lx",
>> +				     orig_insn->sec->name,
>> +				     orig_insn->offset);
>> +				continue;
>> +			}
>> +
> 
> I think WARN_FUNC() can be used here instead.
> 

I'll do that.

Thanks,

-- 
Julien Thierry