Re: [PATCH v5 04/13] module: Move livepatch support to a separate file

Aaron Tomlin
2022-02-10T17:20:36Z

On Thu 2022-02-10 11:44 +0000, Christophe Leroy wrote:
> This change is wrong, build fails with it because is_livepatch_module()
> is nowhere defined.

Yes, sorry about that. This was an omission/or oversight during the rebase
attempt.

> You could move is_livepatch_module() to include/linux/livepatch.h but as
> a separate patch.

Fair enough. Albeit, I'd prefer to revert and keep is_livepatch_module()
in include/linux/module.h - this is likely the best solution.
Note: set_livepatch_module() will remain for internal use only.

> > #else /* !CONFIG_LIVEPATCH */
> > static inline bool is_livepatch_module(struct module *mod)
> > {
> > diff --git a/kernel/module/Makefile b/kernel/module/Makefile
> > index 2902fc7d0ef1..ee20d864ad19 100644
> > --- a/kernel/module/Makefile
> > +++ b/kernel/module/Makefile
> > @@ -7,3 +7,6 @@ obj-$(CONFIG_MODULES) += main.o
> > obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
> > obj-$(CONFIG_MODULE_SIG) += signing.o
> > obj-$(CONFIG_MODULE_SIG_FORMAT) += signature.o
> > +ifdef CONFIG_MODULES
>
> CONFIG_LIVEPATCH depends on CONFIG_MODULES so this ifdef is not needed

Agreed.

> Checkpatch reports the following:
>
> WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
> #80:
> new file mode 100644
>
> CHECK: Comparison to NULL could be written "!mod->klp_info"
> #109: FILE: kernel/module/livepatch.c:25:
> + if (mod->klp_info == NULL)
>
> CHECK: Comparison to NULL could be written "!mod->klp_info->sechdrs"
> #119: FILE: kernel/module/livepatch.c:35:
> + if (mod->klp_info->sechdrs == NULL) {
>
> CHECK: Comparison to NULL could be written "!mod->klp_info->secstrings"
> #127: FILE: kernel/module/livepatch.c:43:
> + if (mod->klp_info->secstrings == NULL) {
>
> CHECK: No space is necessary after a cast
> #142: FILE: kernel/module/livepatch.c:58:
> + mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long)
> mod->core_kallsyms.symtab;

Ok.

> Given how simple this function is, it should be a 'static inline' in
> internal.c

Agreed.

> CHECK: Alignment should match open parenthesis
> #285: FILE: kernel/module/main.c:3033:
> + pr_err("%s: module is marked as livepatch module, but livepatch
> support is disabled",
> + mod->name);

Fair enough.

Kind regards,

--
Aaron Tomlin