linux-kernel - Re: [BUG] git 2.6.31-rc3'ish: "<kobject> does not have a release() function, it is broken and must be fixed."

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Date:	Thu, 06 Aug 2009 13:28:01 -0700
From:	Roland Dreier <rdreier@...co.com>
To:	Greg KH <gregkh@...e.de>
Cc:	Andreas Mohr <andi@...as.de>, linux-kernel@...r.kernel.org,
	rusty@...tcorp.com.au
Subject: Re: [BUG] git 2.6.31-rc3'ish: "<kobject> does not have a release() function, it is broken and must be fixed."


 > > The error happening _before_ module _init() and _after_ module _exit()
 > > clearly points to something outside of an individual driver's control,
 > > i.e. a module core code bug, as hinted by Greg.
 > > 
 > > x86_32 UP, Debian testing, module-init-tools 3.9-2, git as of yesterday.
 > 
 > I can't duplicate this here at all.  I wonder what the difference is.
 > No one has touched this code path in a while, any chance you could run
 > 'git bisect' to track this down?

I don't understand how you can't duplicate it.  I see it here too
(missing release warning on module unload with kobject debugging turned
on) and it's obvious why it's happening from looking at the code;
lib/kobject.c has:

	struct kobj_type *t = get_ktype(kobj);
	//...
	if (t && !t->release)
		pr_debug("kobject: '%s' (%p): does not have a release() "
			 "function, it is broken and must be fixed.\n",
			 kobject_name(kobj), kobj);

and kernel/params.c has:

struct kobj_type module_ktype = {
	.sysfs_ops =	&module_sysfs_ops,
};

ie a ktype with no release method.  And indeed, the release method was
removed in:

commit 7a6a41615bfb2f03ce797bc24104c50b42c935e5
Author: Greg Kroah-Hartman <gregkh@...e.de>
Date:   Sat Dec 22 21:18:25 2007 -0800

    Modules: remove unneeded release function

ie you did it yourself!

What's the deal?

 - R.
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