Re: [PATCH net v3 2/2] mlx5: fix possible ptp queue fifo use-after-free

[kernel test robot <lkp@intel.com>]

Hi Vadim,

I love your patch! Perhaps something to improve:

[auto build test WARNING on net/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Vadim-Fedorenko/mlx5-fix-skb-leak-while-fifo-resync-and-push/20230128-120805
patch link:    https://lore.kernel.org/r/20230126010206.13483-3-vfedorenko%40novek.ru
patch subject: [PATCH net v3 2/2] mlx5: fix possible ptp queue fifo use-after-free
config: i386-randconfig-a015 (https://download.01.org/0day-ci/archive/20230129/202301290020.2pCidjI4-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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
        # https://github.com/intel-lab-lkp/linux/commit/2516a9785583b92ac82262a813203de696096ccd
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Vadim-Fedorenko/mlx5-fix-skb-leak-while-fifo-resync-and-push/20230128-120805
        git checkout 2516a9785583b92ac82262a813203de696096ccd
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/net/ethernet/mellanox/mlx5/core/

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

All warnings (new ones prefixed by >>):

>> drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c:93:18: warning: unused variable 'skb' [-Wunused-variable]
           struct sk_buff *skb;
                           ^
>> drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c:92:30: warning: unused variable 'hwts' [-Wunused-variable]
           struct skb_shared_hwtstamps hwts = {};
                                       ^
   drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c:102:2: error: expected identifier or '('
           while (skb_cc != skb_id && (skb = mlx5e_skb_fifo_pop(&ptpsq->skb_fifo))) {
           ^
   drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c:110:2: error: expected identifier or '('
           if (!skb)
           ^
   drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c:113:2: error: expected identifier or '('
           return true;
           ^
   drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c:114:1: error: extraneous closing brace ('}')
   }
   ^
   2 warnings and 4 errors generated.


vim +/skb +93 drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c

58a518948f6015 Aya Levin       2022-07-04   88  
2516a9785583b9 Vadim Fedorenko 2023-01-26   89  static bool mlx5e_ptp_skb_fifo_ts_cqe_resync(struct mlx5e_ptpsq *ptpsq, u16 skb_cc,
83256998eee9fa Vadim Fedorenko 2023-01-26   90  					     u16 skb_id, int budget)
58a518948f6015 Aya Levin       2022-07-04   91  {
58a518948f6015 Aya Levin       2022-07-04  @92  	struct skb_shared_hwtstamps hwts = {};
58a518948f6015 Aya Levin       2022-07-04  @93  	struct sk_buff *skb;
58a518948f6015 Aya Levin       2022-07-04   94  
58a518948f6015 Aya Levin       2022-07-04   95  	ptpsq->cq_stats->resync_event++;
58a518948f6015 Aya Levin       2022-07-04   96  
2516a9785583b9 Vadim Fedorenko 2023-01-26   97  	if (skb_cc > skb_id || PTP_WQE_CTR2IDX(ptpsq->skb_fifo_pc) < skb_id)
2516a9785583b9 Vadim Fedorenko 2023-01-26   98  		pr_err_ratelimited("mlx5e: out-of-order ptp cqe\n");
2516a9785583b9 Vadim Fedorenko 2023-01-26   99  		return false;
2516a9785583b9 Vadim Fedorenko 2023-01-26  100  	}
2516a9785583b9 Vadim Fedorenko 2023-01-26  101  
2516a9785583b9 Vadim Fedorenko 2023-01-26  102  	while (skb_cc != skb_id && (skb = mlx5e_skb_fifo_pop(&ptpsq->skb_fifo))) {
58a518948f6015 Aya Levin       2022-07-04  103  		hwts.hwtstamp = mlx5e_skb_cb_get_hwts(skb)->cqe_hwtstamp;
58a518948f6015 Aya Levin       2022-07-04  104  		skb_tstamp_tx(skb, &hwts);
58a518948f6015 Aya Levin       2022-07-04  105  		ptpsq->cq_stats->resync_cqe++;
83256998eee9fa Vadim Fedorenko 2023-01-26  106  		napi_consume_skb(skb, budget);
58a518948f6015 Aya Levin       2022-07-04  107  		skb_cc = PTP_WQE_CTR2IDX(ptpsq->skb_fifo_cc);
58a518948f6015 Aya Levin       2022-07-04  108  	}
2516a9785583b9 Vadim Fedorenko 2023-01-26  109  
2516a9785583b9 Vadim Fedorenko 2023-01-26  110  	if (!skb)
2516a9785583b9 Vadim Fedorenko 2023-01-26  111  		return false;
2516a9785583b9 Vadim Fedorenko 2023-01-26  112  
2516a9785583b9 Vadim Fedorenko 2023-01-26  113  	return true;
58a518948f6015 Aya Levin       2022-07-04  114  }
58a518948f6015 Aya Levin       2022-07-04  115  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests