Date: Thu, 10 Dec 2009 22:01:10 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Greg KH <gregkh@suse.de>
cc: LKML <linux-kernel@vger.kernel.org>, Kay Sievers <kay.sievers@vrfy.org>
Subject: Re: [patch] drivers: Fix bogus 0 error return in device_add()
In-Reply-To: <20091210205623.GA29097@suse.de>
Message-ID: <alpine.LFD.2.00.0912102158590.3089@localhost.localdomain>
References: <20091210193057.799393067@linutronix.de> <20091210205623.GA29097@suse.de>
User-Agent: Alpine 2.00 (LFD 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1221
Lines: 29

On Thu, 10 Dec 2009, Greg KH wrote:
> On Thu, Dec 10, 2009 at 07:32:49PM -0000, Thomas Gleixner wrote:
> > If device_add() is called with a device which does not have dev->p set
> > up, then device_private_init() is called. If that succeeds, then the
> > error variable is set to 0. Now if the dev_name(dev) check further
> > down fails, then device_add() correctly terminates, but returns 0.
> > That of course lets the driver progress. If later another driver uses
> > this half set up device as parent then device_add() of the child
> > device explodes and renders sysfs completely unusable.
> > 
> > Set the error to -EINVAL if dev_name() check fails.
> 
> That's a good catch, thanks.
> 
> Is anything currently triggering this?  Or did you just find it by
> reading the code?

Hans-Juergen had a buggy vendor driver where init_name was not
initialized. So the driver probing succeeded and after that a
depending driver crashed somewhere in device_add().

Thanks,

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