Re: [PATCH] mm/kfence: fix a potential NULL pointer dereference

[kernel test robot]

Hi,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on hnaz-mm/master]

url:    https://github.com/intel-lab-lkp/linux/commits/cgel-zte-gmail-com/mm-kfence-fix-a-potential-NULL-pointer-dereference/20220427-151258
base:   https://github.com/hnaz/linux-mm master
config: parisc-allyesconfig (https://download.01.org/0day-ci/archive/20220427/202204271645.QTJoeela-lkp@xxxxxxxxx/config)
compiler: hppa-linux-gcc (GCC) 11.3.0
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/920e9e639493bc72bee803c763f09760e3acd063
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review cgel-zte-gmail-com/mm-kfence-fix-a-potential-NULL-pointer-dereference/20220427-151258
        git checkout 920e9e639493bc72bee803c763f09760e3acd063
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=parisc SHELL=/bin/bash mm/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

   mm/kfence/core.c: In function '__try_free_kfence_meta':
   mm/kfence/core.c:1067:37: error: 'addr' undeclared (first use in this function)
    1067 |                 kfence_guarded_free(addr, meta, false);
         |                                     ^~~~
   mm/kfence/core.c:1067:37: note: each undeclared identifier is reported only once for each function it appears in
   mm/kfence/core.c: In function '__kfence_free':
>> mm/kfence/core.c:1075:37: warning: passing argument 1 of 'kfence_report_error' makes integer from pointer without a cast [-Wint-conversion]
    1075 |                 kfence_report_error(addr, false, NULL, NULL, KFENCE_ERROR_INVALID);
         |                                     ^~~~
         |                                     |
         |                                     void *
   In file included from mm/kfence/core.c:37:
   mm/kfence/kfence.h:129:40: note: expected 'long unsigned int' but argument is of type 'void *'
     129 | void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs,
         |                          ~~~~~~~~~~~~~~^~~~~~~


vim +/kfence_report_error +1075 mm/kfence/core.c

  1069	
  1070	void __kfence_free(void *addr)
  1071	{
  1072		struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr);
  1073	
  1074		if (!meta) {
> 1075			kfence_report_error(addr, false, NULL, NULL, KFENCE_ERROR_INVALID);
  1076			return;
  1077		}
  1078	
  1079		__try_free_kfence_meta(meta);
  1080	}
  1081	

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