Re: [PATCH net-next v5 10/11] igc: Check incompatible configs for Frame Preemption

[kernel test robot <yujie.liu@intel.com>]

Hi Vinicius,

Thanks for your patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Vinicius-Costa-Gomes/ethtool-Add-support-for-frame-preemption/20220520-092800
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git df98714e432abf5cbdac3e4c1a13f94c65ddb8d3
config: arm-randconfig-c002-20220522 (https://download.01.org/0day-ci/archive/20220522/202205221852.CJ4p5boS-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 1443dbaba6f0e57be066995db9164f89fb57b413)
reproduce (this is a W=1 build):
         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
         chmod +x ~/bin/make.cross
         # install arm cross compiling tool for clang build
         # apt-get install binutils-arm-linux-gnueabi
         # https://github.com/intel-lab-lkp/linux/commit/a42e940bc53c40ee4e33a1bbf022a663bb28a9c7
         git remote add linux-review https://github.com/intel-lab-lkp/linux
         git fetch --no-tags linux-review Vinicius-Costa-Gomes/ethtool-Add-support-for-frame-preemption/20220520-092800
         git checkout a42e940bc53c40ee4e33a1bbf022a663bb28a9c7
         # save the config file
         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm clang-analyzer

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <yujie.liu@intel.com>


clang-analyzer warnings: (new ones prefixed by >>)

 >> drivers/net/ethernet/intel/igc/igc_main.c:5919:6: warning: Access to field 'preemptible' results in a dereference of an undefined pointer value (loaded from variable 'ring') [clang-analyzer-core.NullDereference]
            if (ring->preemptible) {
                ^

vim +5919 drivers/net/ethernet/intel/igc/igc_main.c

5f2958052c5820 Vinicius Costa Gomes 2019-12-02  5910
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5911  static int igc_save_launchtime_params(struct igc_adapter *adapter, int queue,
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5912  				      bool enable)
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5913  {
82faa9b799500f Vinicius Costa Gomes 2020-02-14 @5914  	struct igc_ring *ring;
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5915
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5916  	if (queue < 0 || queue >= adapter->num_tx_queues)
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5917  		return -EINVAL;
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5918
a42e940bc53c40 Vinicius Costa Gomes 2022-05-19 @5919  	if (ring->preemptible) {
a42e940bc53c40 Vinicius Costa Gomes 2022-05-19  5920  		netdev_err(adapter->netdev, "Cannot enable LaunchTime on a preemptible queue\n");
a42e940bc53c40 Vinicius Costa Gomes 2022-05-19  5921  		return -EINVAL;
a42e940bc53c40 Vinicius Costa Gomes 2022-05-19  5922  	}
a42e940bc53c40 Vinicius Costa Gomes 2022-05-19  5923
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5924  	ring = adapter->tx_ring[queue];
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5925  	ring->launchtime_enable = enable;
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5926
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5927  	return 0;
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5928  }
82faa9b799500f Vinicius Costa Gomes 2020-02-14  5929

-- 
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