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Date: Thu, 21 Mar 2024 21:05:35 +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: <0efe132b-b343-4438-bb00-5a4b82722ed3@moroto.mountain>
Subject: Re: [PATCH v2 net] ice: Fix freeing uninitialized pointers
Content-Language: en-GB
From: Markus Elfring <Markus.Elfring@web.de>
In-Reply-To: <0efe132b-b343-4438-bb00-5a4b82722ed3@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.

Will any adjustments become relevant also for this change description
if scope reductions would become more appealing for affected local variables?

How much can a small script (like the following) for the semantic patch language
(Coccinelle software) help to achieve a better common understanding for
possible source code transformations?

// See also:
// drivers/net/ethernet/intel/ice/ice_common.c
@movement1@
attribute name __free;
@@
-struct ice_aqc_get_phy_caps_data *pcaps __free(kfree);
 ... when any
+struct ice_aqc_get_phy_caps_data *
 pcaps
+__free(kfree)
 = kzalloc(sizeof(*pcaps), ...);

@movement2@
attribute name __free;
@@
-void *mac_buf __free(kfree);
 ... when any
+void *
 mac_buf
+__free(kfree)
 = kcalloc(2, sizeof(struct ice_aqc_manage_mac_read_resp), ...);

// See also:
// drivers/net/ethernet/intel/ice/ice_ethtool.c
@movement3@
attribute name __free;
@@
-u8 *tx_frame __free(kfree);
 int i;
 ... when any
 if (ice_fltr_add_mac(test_vsi, ...))
 { ... }
+
+{
+u8 *tx_frame __free(kfree) = NULL;
 if (ice_lbtest_create_frame(pf, &tx_frame, ...))
 { ... }
 ... when any
+}
+
 valid_frames = ice_lbtest_receive_frames(...);


Regards,
Markus