Software nodes depend on kernel_kobj which is initialized pretty late
into the boot process - as a core_initcall(). Ahead of moving the
software node initialization to driver_init() we must first make
kernel_kobj available before it.

Make ksysfs_init() visible in the kobject.h header and call it in
do_basic_setup() right before driver_init().

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
 include/linux/kobject.h | 2 ++
 init/main.c             | 1 +
 kernel/ksysfs.c         | 8 +++-----
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index c8219505a79f98bc370e52997efc8af51833cfda..71b9086621c35b7e4ef99b9d3b6707db23faf58c 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -219,4 +219,6 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
 __printf(2, 3)
 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
 
+void ksysfs_init(void);
+
 #endif /* _KOBJECT_H_ */
diff --git a/init/main.c b/init/main.c
index 8b7633b7ab720b9c13a231d64291d35d3852602c..1a9046b563e469057cca72ce39a0701c9c4d49e1 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1482,6 +1482,7 @@ static void __init do_initcalls(void)
 static void __init do_basic_setup(void)
 {
 	cpuset_init_smp();
+	ksysfs_init();
 	driver_init();
 	init_irq_proc();
 	do_ctors();
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index a9e6354d9e2579317d3b1bcb54223432d3ce0950..ac546562a6a1202a752de2d36719c6a193520a79 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -213,7 +213,7 @@ static const struct attribute_group kernel_attr_group = {
 	.attrs = kernel_attrs,
 };
 
-static int __init ksysfs_init(void)
+void __init ksysfs_init(void)
 {
 	int error;
 
@@ -234,14 +234,12 @@ static int __init ksysfs_init(void)
 			goto group_exit;
 	}
 
-	return 0;
+	return;
 
 group_exit:
 	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
 kset_exit:
 	kobject_put(kernel_kobj);
 exit:
-	return error;
+	pr_err("failed to initialize the kernel kobject: %d\n", error);
 }
-
-core_initcall(ksysfs_init);

-- 
2.47.3

On Mon Mar 30, 2026 at 2:40 PM CEST, Bartosz Golaszewski wrote:
> diff --git a/include/linux/kobject.h b/include/linux/kobject.h
> index c8219505a79f98bc370e52997efc8af51833cfda..71b9086621c35b7e4ef99b9d3b6707db23faf58c 100644
> --- a/include/linux/kobject.h
> +++ b/include/linux/kobject.h
> @@ -219,4 +219,6 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
>  __printf(2, 3)
>  int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
>  
> +void ksysfs_init(void);

NIT: I'm aware there's also all the core kobjects in include/linux/kobject.h,
but maybe a separate header would be a better fit.

On Mon, Mar 30, 2026 at 3:47 PM Danilo Krummrich <dakr@kernel.org> wrote:
>
> On Mon Mar 30, 2026 at 2:40 PM CEST, Bartosz Golaszewski wrote:
> > diff --git a/include/linux/kobject.h b/include/linux/kobject.h
> > index c8219505a79f98bc370e52997efc8af51833cfda..71b9086621c35b7e4ef99b9d3b6707db23faf58c 100644
> > --- a/include/linux/kobject.h
> > +++ b/include/linux/kobject.h
> > @@ -219,4 +219,6 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
> >  __printf(2, 3)
> >  int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
> >
> > +void ksysfs_init(void);
>
> NIT: I'm aware there's also all the core kobjects in include/linux/kobject.h,
> but maybe a separate header would be a better fit.

Do you mean moving all the top-level kobject declarations
(kernel_kobj, firmware_kobj, etc.) out of kobject.h into this new
header (ksysfs.h?) along with their init functions?

Bart

On Mon Mar 30, 2026 at 4:19 PM CEST, Bartosz Golaszewski wrote:
> On Mon, Mar 30, 2026 at 3:47 PM Danilo Krummrich <dakr@kernel.org> wrote:
>>
>> On Mon Mar 30, 2026 at 2:40 PM CEST, Bartosz Golaszewski wrote:
>> > diff --git a/include/linux/kobject.h b/include/linux/kobject.h
>> > index c8219505a79f98bc370e52997efc8af51833cfda..71b9086621c35b7e4ef99b9d3b6707db23faf58c 100644
>> > --- a/include/linux/kobject.h
>> > +++ b/include/linux/kobject.h
>> > @@ -219,4 +219,6 @@ int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
>> >  __printf(2, 3)
>> >  int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
>> >
>> > +void ksysfs_init(void);
>>
>> NIT: I'm aware there's also all the core kobjects in include/linux/kobject.h,
>> but maybe a separate header would be a better fit.
>
> Do you mean moving all the top-level kobject declarations
> (kernel_kobj, firmware_kobj, etc.) out of kobject.h into this new
> header (ksysfs.h?) along with their init functions?

I think the top-level kobjects are fine; it's just ksysfs_init() that somehow
feels odd to me being placed in kobject.h.

The top-level kobject do make sense as they are the base for a lot of other
kobjects being created by other core code.

Whereas ksysfs_init() is a ksysfs specific thing that is only ever used by
init/main.c, i.e. other than the top-level kobjects, it has nothing to do with
the kobject API itself.