Re: [PATCH 5.4 03/74] module: merge repetitive strings in module_sig_check()

Sasha Levin
2021-04-05T16:14:47Z

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@perches.com>
>>>> Reviewed-by: Miroslav Benes <mbenes@suse.cz>
>>>> Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
>>>> Signed-off-by: Jessica Yu <jeyu@kernel.org>
>>>> Signed-off-by: Sasha Levin <sashal@kernel.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