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From: Julia Lawall <Julia.Lawall@inria.fr>
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Subject: Re: [PATCH net] ice: Fix freeing uninitialized pointers
Date: Thu, 21 Mar 2024 16:20:09 -0400
Message-Id: <F2FBADE8-EDF9-4987-A97B-CF4D2D1452E0@inria.fr>
References: <e5172afb-427b-423e-877a-10352cf4a007@web.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
 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>,
 LKML <linux-kernel@vger.kernel.org>,
 Alexander Lobakin <aleksander.lobakin@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>,
 Kees Cook <keescook@chromium.org>,
 Lukasz Czapnik <lukasz.czapnik@intel.com>, Paolo Abeni <pabeni@redhat.com>,
 Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com>
In-Reply-To: <e5172afb-427b-423e-877a-10352cf4a007@web.de>
To: Markus Elfring <Markus.Elfring@web.de>

Does one prefer an initialization of null at the top of the function or an i=
nitialization to a meaningful value in the middle of the function ?

(Sorry for top posting)


Sent from my iPhone

> On 21 Mar 2024, at 14:14, Markus Elfring <Markus.Elfring@web.de> wrote:
>=20
> =EF=BB=BF
>>=20
>>> How do you think about to reduce the scope for the affected local variab=
le instead
>>> with the help of a small script (like the following) for the semantic pa=
tch language?
>>>=20
>>> @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(...);
>>=20
>> I believe you don't understand what the scope of the above can be.
>=20
> Will the understanding improve for the proposed source code transformation=
?
>=20
> Regards,
> Markus