Re: [PATCH next] wifi: iwlwifi: Fix uninitialized variable with __free()

[Dan Carpenter]

On Wed, Mar 12, 2025 at 08:15:18AM -0700, Jeff Johnson wrote:
> On 3/12/2025 1:31 AM, Dan Carpenter wrote:
> > Pointers declared with the __free(kfree) attribute need to be initialized
> > because they will be passed to kfree() on every return path.  There are
> > two return statement before the "cmd" pointer is initialized so this
> > leads to an uninitialized variable bug.
> > 
> > Fixes: d1e879ec600f ("wifi: iwlwifi: add iwlmld sub-driver")
> > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > ---
> >  drivers/net/wireless/intel/iwlwifi/mld/debugfs.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/wireless/intel/iwlwifi/mld/debugfs.c b/drivers/net/wireless/intel/iwlwifi/mld/debugfs.c
> > index c759c5c68dc0..1d4b2ad5d388 100644
> > --- a/drivers/net/wireless/intel/iwlwifi/mld/debugfs.c
> > +++ b/drivers/net/wireless/intel/iwlwifi/mld/debugfs.c
> > @@ -556,8 +556,8 @@ iwl_dbgfs_vif_twt_setup_write(struct iwl_mld *mld, char *buf, size_t count,
> >  	};
> >  	struct ieee80211_vif *vif = data;
> >  	struct iwl_mld_vif *mld_vif = iwl_mld_vif_from_mac80211(vif);
> > +	struct iwl_dhc_cmd *cmd __free(kfree) = NULL;
> 
> hmm, I thought the recommended convention was to define __free() pointers at
> the point of allocation. cleanup.h explicitly says:
> 
>  * Given that the "__free(...) = NULL" pattern for variables defined at
>  * the top of the function poses this potential interdependency problem
>  * the recommendation is to always define and assign variables in one
>  * statement and not group variable definitions at the top of the
>  * function when __free() is used.
> 

People do it either way.  I'm agnostic so long as it doesn't have bugs.

regards,
dan carpenter