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Date: Thu, 21 Mar 2024 18:59:00 +0100
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To: Dan Carpenter <dan.carpenter@linaro.org>,
 kernel-janitors@vger.kernel.org, netdev@vger.kernel.org,
 intel-wired-lan@lists.osuosl.org,
 Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
 Przemek Kitszel <przemyslaw.kitszel@intel.com>,
 Tony Nguyen <anthony.l.nguyen@intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
 Alexander Lobakin <aleksander.lobakin@intel.com>,
 Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
 David Laight <David.Laight@aculab.com>, "David S. Miller"
 <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>,
 Jakub Kicinski <kuba@kernel.org>,
 Jesse Brandeburg <jesse.brandeburg@intel.com>, Jiri Pirko
 <jiri@resnulli.us>, Jonathan Cameron <jic23@kernel.org>,
 Julia Lawall <julia.lawall@inria.fr>, Kees Cook <keescook@chromium.org>,
 Lukasz Czapnik <lukasz.czapnik@intel.com>, Paolo Abeni <pabeni@redhat.com>,
 Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com>
References: <77145930-e3df-4e77-a22d-04851cf3a426@moroto.mountain>
Subject: Re: [PATCH net] ice: Fix freeing uninitialized pointers
Content-Language: en-GB
From: Markus Elfring <Markus.Elfring@web.de>
In-Reply-To: <77145930-e3df-4e77-a22d-04851cf3a426@moroto.mountain>
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> Automatically cleaned up pointers need to be initialized before exiting
> their scope.  In this case, they need to be initialized to NULL before
> any return statement.

How will development interests evolve further for such design aspects?


=E2=80=A6
> +++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
> @@ -941,11 +941,11 @@ static u64 ice_loopback_test(struct net_device *ne=
tdev)
>  	struct ice_netdev_priv *np =3D netdev_priv(netdev);
>  	struct ice_vsi *orig_vsi =3D np->vsi, *test_vsi;
>  	struct ice_pf *pf =3D orig_vsi->back;
> +	u8 *tx_frame __free(kfree) =3D NULL;
>  	u8 broadcast[ETH_ALEN], ret =3D 0;
>  	int num_frames, valid_frames;
>  	struct ice_tx_ring *tx_ring;
>  	struct ice_rx_ring *rx_ring;
> -	u8 *tx_frame __free(kfree);
>  	int i;
>
>  	netdev_info(netdev, "loopback test\n");

How do you think about to reduce the scope for the affected local variable=
 instead
with the help of a small script (like the following) for the semantic patc=
h language?

@movement@
attribute name __free;
@@
-u8 *tx_frame __free(kfree);
 int i;
 ... when any
 if (ice_fltr_add_mac(test_vsi, ...))
 { ... }
+
+{
+u8 *tx_frame __free(kfree) =3D NULL;
 if (ice_lbtest_create_frame(pf, &tx_frame, ...))
 { ... }
 ... when any
+}
+
 valid_frames =3D ice_lbtest_receive_frames(...);


Regards,
Markus