Re: [PATCH net] core: Don't attempt to load the "" driver.

[Stephen Hemminger <stephen@networkplumber.org>]

On Wed, 3 Sep 2014 10:02:26 -0700
Cong Wang <cwang@twopensource.com> wrote:

> On Wed, Sep 3, 2014 at 2:02 AM, David Laight <David.Laight@aculab.com> wrote:
> >> On Tue, Sep 2, 2014 at 6:48 AM, David Laight <David.Laight@aculab.com> wrote:
> >> > While the applications shouldn't be calling an SIOCxxx ioctl with ifr_name[0] == 0
> >> > the kernel shouldn't be tracing the error either.
> >> >
> >>
> >> Why don't we reject this empty string? It doesn't look like a valid one.
> >> I assume this is for compatibility?
> >
> > The ioctl code will error it later on - the module load is 'speculative'.
> > Analysing whether all the ioctls need dev_load() to succeed is another issue.
> >
> > Indeed I'm not sure anything stops the module being unloaded before the
> > ioctl action tries to take a real reference on the interface.
> >
> > Whether request_module("") should be an error is a different question,
> > probably much harder to analyse.
> >
> 
> If an empty string is an invalid name, we definitely should reject it from
> the very beginning, so that you would not need to worry about the above
> issues.
> 
> Something like the attached patch.

This will break for many things where the code randomly tries
to load something based on name, but the module is already there.