Re: [PATCH 2/2] staging: emxx_udc: test returned value

[Julia Lawall <julia.lawall@lip6.fr>]

On Sat, 4 Apr 2015, Dan Carpenter wrote:

> On Sat, Apr 04, 2015 at 06:20:53PM +0200, Julia Lawall wrote:
> > Couldn't one say:
> > 
> > x = NULL;
> > y = &x->whatever;
> > z = container_of(y, struct blah, whatever);
> > 
> > and end up with z being NULL?
> 
> That is crazy person code.  It looks deliberately wrong.  If we start
> merging deliberate mistakes then we're already screwed.
> 
> I have a smatch check which warns on container_of() but I should update
> it to not complain if it's the first struct member.  I have looked at
> quite a few of these warnings and I worry that there are some places
> where it relies on container_of() to be a no-op...  That's also crazy
> but it's the kind of crazy that people do in real life.  :P

OK.  Should I update the patch to remove the test?

I find 57 NULL tests on the result of container_of in the kernel as a 
whole.

julia