On Tue, Jul 14, 2026 at 04:46:08PM +0200, Petr Pavlu wrote:
> > @@ -734,7 +734,9 @@
> > EARLYCON_TABLE() \
> > LSM_TABLE() \
> > EARLY_LSM_TABLE() \
> > - KUNIT_INIT_TABLE()
> > + KUNIT_INIT_TABLE() \
> > + . = ALIGN(8); \
>
> Is ALIGN(8) sufficient, or is STRUCT_ALIGN() needed instead?
Hi Petr,
Thank you for your feedback.
I can use STRUCT_ALIGN() instead of ALIGN(8) to match structure alignment.
> > + BOUNDED_SECTION_PRE_LABEL(.initcall.modnames, initcall_modnames,
> > __start_, __stop_)
>
> Nit: I think this can be shortened to:
>
> BOUNDED_SECTION_BY(.initcall.modnames, _initcall_modnames)
Acknowledged.
> > #define INIT_TEXT \
> > *(.init.text .init.text.*) \
> > diff --git a/include/linux/init.h b/include/linux/init.h
> > index 40331923b9f4..9c78b6c30361 100644
> > --- a/include/linux/init.h
> > +++ b/include/linux/init.h
> > @@ -271,8 +271,30 @@ extern struct module __this_module;
> > __initcall_name(initcall, __iid, id), \
> > __initcall_section(__sec, __iid))
> >
> > -#define ___define_initcall(fn, id, __sec) \
> > - __unique_initcall(fn, id, __sec, __initcall_id(fn))
> > +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
> > +#define __initcall_fn_ptr(fn, __iid, id) __initcall_stub(fn, __iid, id)
> > +#else
> > +#define __initcall_fn_ptr(fn, __iid, id) fn
> > +#endif
> > +
> > +struct initcall_modname {
> > + initcall_t initcall_fn;
> > + const char *modname;
> > +};
> > +
> > +#define ____define_initcall_modname(fn, id, __sec, __iid) \
> > + __unique_initcall(fn, id, __sec, __iid) \
> > + static const char __initstr_##fn[] __used __aligned(1) \
> > + __section(".init.rodata") = KBUILD_MODNAME; \
> > + static const struct initcall_modname __modname_##fn __used \
> > + __section(".initcall.modnames") = { \
> > + .initcall_fn = __initcall_fn_ptr(fn, __iid, id), \
> > + .modname = __initstr_##fn \
> > + };
>
> All initcalls are ultimately defined via ____define_initcall_modname(),
> including initcalls in vmlinux code that can never be built as modules.
> In such a case, KBUILD_MODNAME is set to the target's basename (same as
> KBUILD_BASENAME).
>
> This wastes memory and also allows the module_blacklist parameter to
> match initcalls that are unrelated to built-in modules.
Agreed.
In the next iteration, I restored the default ___define_initcall definition
in include/linux/init.h back to using the standard __unique_initcall
without mapping.
To restrict the mapping strictly to actual built-in modules, I redefined
module_init() under #ifndef MODULE in include/linux/module.h to expand to
____define_initcall_modname().
Indeed since core vmlinux code that can never be built as modules does not
use module_init(), the next iteration ensures that:
1. No mapping metadata is generated for core subsystem initcalls
2. The module_blacklist (or module_denylist) parameters can no longer
accidentally match or skip unrelated core kernel initcalls
> > +
> > +#define ___define_initcall(fn, id, __sec) \
> > + ____define_initcall_modname(fn, id, __sec, __initcall_id(fn))
> > +
> >
> > #define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
> >
> > diff --git a/include/linux/module.h b/include/linux/module.h
> > index 7566815fabbe..bc2968c225e1 100644
> > --- a/include/linux/module.h
> > +++ b/include/linux/module.h
> > @@ -883,6 +883,8 @@ static inline void
> > module_for_each_mod(int(*func)(struct module *mod, void *data
> > }
> > #endif /* CONFIG_MODULES */
> >
> > +extern bool module_is_denylisted(const char *module_name);
> > +
>
> Nit: The extern keyword in function declarations is unnecessary. See
> Documentation/process/coding-style.rst.
Acknowledged.
>
> > #ifdef CONFIG_SYSFS
> > extern struct kset *module_kset;
> > extern const struct kobj_type module_ktype;
> > diff --git a/init/main.c b/init/main.c
> > index e363232b428b..af71811d24e3 100644
> > --- a/init/main.c
> > +++ b/init/main.c
> > @@ -1334,12 +1334,65 @@ static inline void do_trace_initcall_level(const
> > char *level)
> > }
> > #endif /* !TRACEPOINTS_ENABLED */
> >
> > +extern struct initcall_modname __start_initcall_modnames[];
> > +extern struct initcall_modname __stop_initcall_modnames[];
> > +
> > +/* module_denylist is a comma-separated list of module names */
> > +static char *module_denylist;
> > +bool module_is_denylisted(const char *module_name)
>
> module_is_denylisted() should be __init_or_module.
Acknowledged.
> > +{
> > + const char *p;
> > + size_t len;
> > +
> > + if (!module_denylist)
> > + return false;
> > +
> > + for (p = module_denylist; *p; p += len) {
> > + len = strcspn(p, ",");
> > + if (strlen(module_name) == len && !memcmp(module_name, p, len))
> > + return true;
> > + if (p[len] == ',')
> > + len++;
> > + }
> > + return false;
> > +}
> > +core_param(module_denylist, module_denylist, charp, 0400);
> > +core_param(module_blacklist, module_denylist, charp, 0400);
> > +
> > +static const char *initcall_get_modname(initcall_t fn)
>
> initcall_get_modname() should ideally be __init.
Acknowledged.
>
> Nit: I think a better name would be something like get_builtin_modname()
> to make clear that the function returns a module name only for built-in
> modules, not regular ones.
Agreed.
> > +{
> > + struct initcall_modname *p;
> > + unsigned long addr = (unsigned long)dereference_function_descriptor(fn);
> > +
> > + if (system_state >= SYSTEM_FREEING_INITMEM)
> > + return NULL;
> > +
> > + if (!is_kernel_text(addr) &&
> > + !is_kernel_inittext(addr))
> > + return NULL;
>
> I believe these checks could be avoided if the code was reorganized to
> avoid reaching this logic on the do_init_module() path in the first
> place.
Agreed.
Kind regards,
--
Aaron Tomlin
