Re: [patch] drivers: Fix bogus 0 error return in device_add()

[Thomas Gleixner <tglx@linutronix.de>]

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