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

[Sasha Levin]

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@xxxxxxxxxxx>
> > > > Reviewed-by: Miroslav Benes <mbenes@xxxxxxx>
> > > > Signed-off-by: Sergey Shtylyov <s.shtylyov@xxxxxxxxxxxx>
> > > > Signed-off-by: Jessica Yu <jeyu@xxxxxxxxxx>
> > > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > > > ---
> > > >  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