linux-kernel - Re: [PATCH 10/14] scsi: osd: fix device

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Date:	Mon, 20 Sep 2010 10:55:06 -0500
From:	James Bottomley <James.Bottomley@...e.de>
To:	Boaz Harrosh <bharrosh@...asas.com>
Cc:	Greg KH <gregkh@...e.de>, Dan Carpenter <error27@...il.com>,
	Vasiliy Kulikov <segooon@...il.com>,
	kernel-janitors@...r.kernel.org,
	Benny Halevy <bhalevy@...asas.com>, Tejun Heo <tj@...nel.org>,
	Arnd Bergmann <arnd@...db.de>, osd-dev@...n-osd.org,
	linux-scsi@...r.kernel.org, cornelia.huck@...ibm.com,
	linux-kernel@...r.kernel.org, Kay Sievers <kay.sievers@...y.org>
Subject: Re: [PATCH 10/14] scsi: osd: fix device_register() error handling

On Mon, 2010-09-20 at 17:42 +0200, Boaz Harrosh wrote:
> I think I have a compromise. If it is indeed the dev_set_name() leak
> then we can just deallocate the name on the error return path. Therefore
> any drivers that have the device embedded and rely on it been freed without
> calling _put will be fine as before. And these calling _put will be fine
> as well.
> 
> See below
> Boaz
> ---
> git diff --stat -p -M drivers/base/core.c
>  drivers/base/core.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index d1b2c9a..054fac2 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -1068,6 +1068,7 @@ done:
>  	if (parent)
>  		put_device(parent);
>  name_error:
> +	kfree(dev->kobj.name);
>  	kfree(dev->p);
>  	dev->p = NULL;
>  	goto done;

That's not really good enough ... it will result in a double free
because the final put (if there is one) will free the name again.

This would work, but it feels a bit wrong to be poking at the kobject
from within the driver core ... perhaps a kobject_free_name() call might
be better?

James

---

diff --git a/drivers/base/core.c b/drivers/base/core.c
index d1b2c9a..88ffaca 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1067,6 +1067,8 @@ done:
 	cleanup_device_parent(dev);
 	if (parent)
 		put_device(parent);
+	kfree(dev->kobj.name);
+	dev->kobj.name = NULL;
 name_error:
 	kfree(dev->p);
 	dev->p = NULL;


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