Re: How to fix CHECK warning: testing a 'safe expression'

Re: How to fix CHECK warning: testing a 'safe expression'

[Josh Triplett]

+linux-sparse

On Fri, Jan 02, 2015 at 09:51:25AM -0500, Murali Karicheri wrote:
> On 12/16/2014 01:23 PM, Murali Karicheri wrote:
> >netdev maintainers,
> >
> >I got a comment to address CHECK warning and wondering how to address
> >'warning: testing a 'safe expression' which appears when using
> >IS_ERR_OR_NULL(foo)
> >
> >where foo is defined as
> >
> >struct foo_type *foo;
> >
> >The foo get assigned only NULL or ERR_PTR(error code). So I believe the
> >usage is correct. But then how do I make the CHECK happy of its usage?
> >
> >I have tried doing a grep on the current usage of IS_ERR_OR_NULL() and
> >found 276 of them causes this warning in the v3.18 version of the kernel
> >that I am using
> >
> >$ grep -r "warning: testing a 'safe expression" * | wc -l
> >276
> >
> >1) Can someone explain what this warning means?
> >
> >2) Is it acceptable to post patches to netdev list with this warning?
> >
> >3) if not, how this is expected to be fixed? Any example usage to fix
> >this warning will be helpful.
> >
> >Thanks in advance for
> 
> 
> -- 
> Murali Karicheri
> Linux Kernel, Texas Instruments