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Subject[PATCH v2] Fix "notes" kobject leak
> > > > --- a/kernel/module.c
> > > > +++ b/kernel/module.c
> > > > @@ -1174,6 +1174,7 @@ static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
> > > > sysfs_remove_bin_file(notes_attrs->dir,
> > > > &notes_attrs->attrs[i]);
> > > > kobject_del(notes_attrs->dir);
> > > > + kobject_put(notes_attrs->dir);
> > >
> > > Hm, no, that should just be a call to kobject_put() instead of
> > > kobject_del(), can you try that instead and see if that solves the issue
> > > (am at a conference and can't test that at the moment, sorry.)
> >
> > Why?! kobject_del() puts parent kobject.
>
> And that's about it (well, it also tears down the sysfs stuff.)
>
> If you call kobject_put() instead, and it's the last put, it will also
> call kobject_del() and do everything else that it needs to do.
>
> Try it and let me know if I'm right or not :)

OK, this works too.


[PATCH v2] Fix "notes" kobject leak

It happens every rmmod if KALLSYMS=y and SYSFS=y.

# modprobe foo

kobject: 'foo' (ffffffffa00743d0): kobject_add_internal: parent: 'module', set: 'module'
kobject: 'holders' (ffff88017e7c5770): kobject_add_internal: parent: 'foo', set: '<NULL>'
kobject: 'foo' (ffffffffa00743d0): kobject_uevent_env
kobject: 'foo' (ffffffffa00743d0): fill_kobj_path: path = '/module/foo'
kobject: 'notes' (ffff88017fa9b668): kobject_add_internal: parent: 'foo', set: '<NULL>'
^^^^^

# rmmod foo

kobject: 'holders' (ffff88017e7c5770): kobject_cleanup
kobject: 'holders' (ffff88017e7c5770): auto cleanup kobject_del
kobject: 'holders' (ffff88017e7c5770): calling ktype release
kobject: (ffff88017e7c5770): dynamic_kobj_release
kobject: 'holders': free name
kobject: 'foo' (ffffffffa00743d0): kobject_cleanup
kobject: 'foo' (ffffffffa00743d0): does not have a release() function, it is broken and must be fixed.
kobject: 'foo' (ffffffffa00743d0): auto cleanup 'remove' event
kobject: 'foo' (ffffffffa00743d0): kobject_uevent_env
kobject: 'foo' (ffffffffa00743d0): fill_kobj_path: path = '/module/foo'
kobject: 'foo' (ffffffffa00743d0): auto cleanup kobject_del
kobject: 'foo': free name

[whooops]

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

kernel/module.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1173,7 +1173,7 @@ static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
while (i-- > 0)
sysfs_remove_bin_file(notes_attrs->dir,
&notes_attrs->attrs[i]);
- kobject_del(notes_attrs->dir);
+ kobject_put(notes_attrs->dir);
}
kfree(notes_attrs);
}

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