Re: [PATCH 3/4] modules: proper cleanup of kobject withoutCONFIG_SYSFS

From: Denis V. Lunev
Date: Thu May 22 2008 - 07:44:48 EST


On Thu, 2008-05-22 at 19:20 +1000, Rusty Russell wrote:
> On Tuesday 20 May 2008 19:59:48 Denis V. Lunev wrote:
> > kobject: '<NULL>' (ffffffffa0104050): is not initialized, yet kobject_put()
>
> Thanks Denis.
>
> This patch masks a deeper problem; looks like you can't load any modules with
> CONFIG_SYSFS=n:
>
> kernel/module.c:
> int mod_sysfs_init(struct module *mod)
> {
> int err;
> struct kobject *kobj;
>
> if (!module_sysfs_initialized) {
> printk(KERN_ERR "%s: module sysfs not initialized\n",
> mod->name);
> err = -EINVAL;
> goto out;
> }
>
> AFAICT, module_sysfs_initialized is not ever set if !CONFIG_SYSFS.
>
> I can't see the point of module_sysfs_initialized. It was introduced by Greg
> in commit 823bccfc ("remove "struct subsystem" as it is no longer needed").
>
> Greg, what were you trying to do here? Modules can't be loaded before
> param_sysfs_init(): are you trying to handle the case where the
> kset_create_and_add() fails?

Basically you miss
static inline int mod_sysfs_init(struct module *mod)
{
return 0;
}
in include/linux/module.h

So, without CONFIG_SYSFS a dummy stab for mod_sysfs_init is called.

Regards,
Den

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