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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1284983897.2973.11.camel@mulgrave.site>
Date:	Mon, 20 Sep 2010 06:58:17 -0500
From:	James Bottomley <James.Bottomley@...e.de>
To:	Dan Carpenter <error27@...il.com>
Cc:	Vasiliy Kulikov <segooon@...il.com>,
	kernel-janitors@...r.kernel.org,
	Boaz Harrosh <bharrosh@...asas.com>,
	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, Greg KH <gregkh@...e.de>,
	Kay Sievers <kay.sievers@...y.org>
Subject: Re: [PATCH 10/14] scsi: osd: fix device_register() error handling

On Sun, 2010-09-19 at 16:26 +0200, Dan Carpenter wrote:
> On Sun, Sep 19, 2010 at 04:55:07PM +0400, Vasiliy Kulikov wrote:
> > If device_register() fails then call put_device().
> > See comment to device_register.
> > 
> > Signed-off-by: Vasiliy Kulikov <segooon@...il.com>
> > ---
> >  compile tested.
> > 
> >  drivers/scsi/osd/osd_uld.c |    4 +++-
> >  1 files changed, 3 insertions(+), 1 deletions(-)
> > 
> > diff --git a/drivers/scsi/osd/osd_uld.c b/drivers/scsi/osd/osd_uld.c
> > index cefb2c0..3e0edc2 100644
> > --- a/drivers/scsi/osd/osd_uld.c
> > +++ b/drivers/scsi/osd/osd_uld.c
> > @@ -474,7 +474,7 @@ static int osd_probe(struct device *dev)
> >  	error = device_register(&oud->class_dev);
> >  	if (error) {
> >  		OSD_ERR("device_register failed => %d\n", error);
> > -		goto err_put_cdev;
> > +		goto err_put_device;
> >  	}
> >  
> >  	get_device(&oud->class_dev);
> > @@ -482,6 +482,8 @@ static int osd_probe(struct device *dev)
> >  	OSD_INFO("osd_probe %s\n", disk->disk_name);
> >  	return 0;
> >  
> 
> Hm...  So if device_register() fails then we should always call
> device_put()?  It seems like a lot of existing code does that but I
> hadn't realized until now that that is how it works.

Heh, it wasn't a bug when most of the code was written.  It became a bug
when dev_set_name() was added because now the storage allocated for the
name has to be freed with a put.  Previous to this, the advice was just
to free the device if device_register() failed.

> Why can't the device_put() just be added inside the device_register() so
> the unwinding works automatically?

Since Greg and Kay didn't actually alter any of the device_register()
failure paths, this does sound to be the better course of action ... of
course, every device_register() introduced after the dev_set_name()
change may call put_device() on the cleanup path ... someone needs to
check.

James


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/