Re: [PATCH v2 2/2] add check for pointers with __free attribute initialized to NULL

[dan.j.williams]

Joe Perches wrote:
> On Fri, 2025-10-24 at 22:59 +0530, Ally Heev wrote:
> > pointers with __free attribute initialized to NULL
> > pose potential cleanup issues [1] when a function uses
> > interdependent variables with cleanup attributes
> > 
> > Link: https://docs.kernel.org/core-api/cleanup.html [1]
> > Link: https://lore.kernel.org/all/68f7b830ec21a_10e910070@dwillia2-mobl4.notmuch/
> > Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> > Signed-off-by: Ally Heev <allyheev@xxxxxxxxx>
> []
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> []
> > @@ -7728,6 +7728,12 @@ sub process {
> >  			ERROR("UNINITIALIZED_PTR_WITH_FREE",
> >  			      "pointer '$1' with __free attribute should be initialized\n" . $herecurr);
> >  		}
> > +
> > +# check for pointers with __free attribute initialized to NULL
> > +		while ($line =~ /\*\s*($Ident)\s+$FreeAttribute\s*=\s*NULL\b/g) {
> > +			WARN("NULL_INITIALIZED_PTR_WITH_FREE",
> > +			      "pointer '$1' with __free attribute should be initialized to a non-NULL address\n" . $herecurr);
> > +		}
> >  	}
> 
> I think this a poor idea as almost all the instances where this
> initialization is done are fine.
> 
> And there are a lot of them.
> 
> $ git grep -P '\b__free\b.*=\s*NULL\s*;' | wc -l
> 490

That is significant. ...but you did say "almost" above. What about
moving this from WARN level to CHK level?

With that change you can add:

Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx>