linux-kernel - Re: [PATCH 5.4 03/74] module: merge repetitive strings in module_sig

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Message-ID: <YGs3SoEiLEW3pWOE@sashalap>
Date:   Mon, 5 Apr 2021 12:14:02 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     Sergey Shtylyov <s.shtylyov@...russia.ru>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Joe Perches <joe@...ches.com>, Miroslav Benes <mbenes@...e.cz>,
        Jessica Yu <jeyu@...nel.org>
Subject: Re: [PATCH 5.4 03/74] module: merge repetitive strings in
 module_sig_check()

On Mon, Apr 05, 2021 at 05:11:13PM +0300, Sergey Shtylyov wrote:
>On 4/5/21 4:40 PM, Greg Kroah-Hartman wrote:
>
>[...]
>>>> [ Upstream commit 705e9195187d85249fbb0eaa844b1604a98fbc9a ]
>>>>
>>>> The 'reason' variable in module_sig_check() points to 3 strings across
>>>> the *switch* statement, all needlessly starting with the same text.
>>>> Let's put the starting text into the pr_notice() call -- it saves 21
>>>> bytes of the object code (x86 gcc 10.2.1).
>>>>
>>>> Suggested-by: Joe Perches <joe@...ches.com>
>>>> Reviewed-by: Miroslav Benes <mbenes@...e.cz>
>>>> Signed-off-by: Sergey Shtylyov <s.shtylyov@...russia.ru>
>>>> Signed-off-by: Jessica Yu <jeyu@...nel.org>
>>>> Signed-off-by: Sasha Levin <sashal@...nel.org>
>>>> ---
>>>>  kernel/module.c | 9 +++++----
>>>>  1 file changed, 5 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/kernel/module.c b/kernel/module.c
>>>> index ab1f97cfe18d..9fe3e9b85348 100644
>>>> --- a/kernel/module.c
>>>> +++ b/kernel/module.c
>>>> @@ -2908,16 +2908,17 @@ static int module_sig_check(struct load_info *info, int flags)
>>>>  		 * enforcing, certain errors are non-fatal.
>>>>  		 */
>>>>  	case -ENODATA:
>>>> -		reason = "Loading of unsigned module";
>>>> +		reason = "unsigned module";
>>>>  		goto decide;
>>>>  	case -ENOPKG:
>>>> -		reason = "Loading of module with unsupported crypto";
>>>> +		reason = "module with unsupported crypto";
>>>>  		goto decide;
>>>>  	case -ENOKEY:
>>>> -		reason = "Loading of module with unavailable key";
>>>> +		reason = "module with unavailable key";
>>>>  	decide:
>>>>  		if (is_module_sig_enforced()) {
>>>> -			pr_notice("%s is rejected\n", reason);
>>>> +			pr_notice("%s: loading of %s is rejected\n",
>>>> +				  info->name, reason);
>>>
>>>    Mhm, in 5.4 there was no printing of 'info->name'...
>>
>> Is that now a problem?
>
>   Looking at 5.4.y, it probably shouldn't be a problem... but I had to go and look. :-)
>   I've found a simple commit that added 'info->name' printing (perhaps should also be
>considered for inclusion?):
>
>https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e9f35f634e099894f4d6c3b039cd3de5281ee637

Ah yes, looks like I squashed it in by mistake. I'll fix it up in the
queue. Thanks!

-- 
Thanks,
Sasha