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

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

[Murali Karicheri]

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

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

[Murali Karicheri]

+ Josh

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

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