From: Rusty Russell <rusty@rustcorp.com.au>
To: Greg KH <gregkh@linuxfoundation.org>,
Li Zhong <zhong@linux.vnet.ibm.com>
Cc: linux-next list <linux-next@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
rmk+kernel@arm.linux.org.uk
Subject: Re: [RFC PATCH next]module: Fix mod->mkobj.kobj potentially freed too early
Date: Thu, 22 Aug 2013 16:30:53 +0930 [thread overview]
Message-ID: <87vc2yciqi.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20130821161819.GA14364@kroah.com>
Greg KH <gregkh@linuxfoundation.org> writes:
> On Wed, Aug 21, 2013 at 05:49:58PM +0800, Li Zhong wrote:
> > struct kobj_type module_ktype = {
> > + .release = module_kobj_release,
> > .sysfs_ops = &module_sysfs_ops,
> > };
>
> Wait, as there is no release function here for the kobject (a different
> problem), why is the deferred release function causing any problems?
> There is no release function to call, so what is causing the oops?
Because DEBUG_KOBJECT_RELEASE does the kobject_put() sometime later,
which is what causes the oops.
Since kobjects don't have an owner field, AFAICT someone *could* grab
one in a module which is unloading, then put it after unload. So this
fixes a real bug, albeit not one seen in the real world.
Applied,
Rusty.
next prev parent reply other threads:[~2013-08-22 7:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-21 9:49 [RFC PATCH next]module: Fix mod->mkobj.kobj potentially freed too early Li Zhong
2013-08-21 16:18 ` Greg KH
2013-08-22 2:34 ` Li Zhong
2013-08-22 4:03 ` Greg KH
2013-08-22 5:37 ` Li Zhong
2013-08-22 7:37 ` [RFC PATCH v2 " Li Zhong
2013-08-22 21:58 ` Greg KH
2013-08-25 4:07 ` Greg KH
2013-08-27 4:38 ` Rusty Russell
2013-08-27 6:21 ` Greg KH
2013-09-01 23:51 ` Rusty Russell
2013-09-02 0:43 ` Greg KH
2013-08-22 7:00 ` Rusty Russell [this message]
2013-08-22 7:50 ` [RFC PATCH " Li Zhong
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