Re: [PATCH v2 05/10] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS

From: Saravana Kannan
Date: Wed Aug 14 2019 - 13:35:23 EST


On Wed, Aug 14, 2019 at 5:54 AM 'Matthias Maennich' via kernel-team
<kernel-team@xxxxxxxxxxx> wrote:
>
> On Tue, Aug 13, 2019 at 01:15:44PM -0700, Saravana Kannan wrote:
> >On Tue, Aug 13, 2019 at 5:19 AM 'Matthias Maennich' via kernel-team
> ><kernel-team@xxxxxxxxxxx> wrote:
> >>
> >> If MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS is enabled (default=n), the
> >> requirement for modules to import all namespaces that are used by
> >> the module is relaxed.
> >>
> >> Enabling this option effectively allows (invalid) modules to be loaded
> >> while only a warning is emitted.
> >>
> >> Disabling this option keeps the enforcement at module loading time and
> >> loading is denied if the module's imports are not satisfactory.
> >>
> >> Reviewed-by: Martijn Coenen <maco@xxxxxxxxxxx>
> >> Signed-off-by: Matthias Maennich <maennich@xxxxxxxxxx>
> >> ---
> >> init/Kconfig | 14 ++++++++++++++
> >> kernel/module.c | 11 +++++++++--
> >> 2 files changed, 23 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/init/Kconfig b/init/Kconfig
> >> index bd7d650d4a99..b3373334cdf1 100644
> >> --- a/init/Kconfig
> >> +++ b/init/Kconfig
> >> @@ -2119,6 +2119,20 @@ config MODULE_COMPRESS_XZ
> >>
> >> endchoice
> >>
> >> +config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
> >> + bool "Allow loading of modules with missing namespace imports"
> >> + default n
> >> + help
> >> + Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
> >> + a namespace. A module that makes use of a symbol exported with such a
> >> + namespace is required to import the namespace via MODULE_IMPORT_NS().
> >> + This option relaxes this requirement when loading a module.
> >
> >> While
> >> + technically there is no reason to enforce correct namespace imports,
> >> + it creates consistency between symbols defining namespaces and users
> >> + importing namespaces they make use of.
> >
> >I'm confused by this sentence. It sounds like it's the opposite of
> >what the config is doing? Can you please reword it for clarify?
>
> How about:
>
> Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
> a namespace. A module that makes use of a symbol exported with such a
> namespace is required to import the namespace via MODULE_IMPORT_NS().
> There is no technical reason to enforce correct namespace imports,
> but it creates consistency between symbols defining namespaces and
> users importing namespaces they make use of. This option relaxes this
> requirement and lifts the enforcement when loading a module.

That's a lot better. Especially moving the "This option relaxes..." to
the bottom. Thanks.

-Saravana