[arm-integrator:b4/virt-to-phys-kfence 2/2] include/linux/kfence.h:58:47: error: 'char *' and 'void *' are not pointers to compatible types

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git b4/virt-to-phys-kfence
head:   709c5a98b878015dc4f8838fca1c0194b42dee86
commit: 709c5a98b878015dc4f8838fca1c0194b42dee86 [2/2] kfence: Use a void * for page pool
config: riscv-randconfig-r042-20230809 (https://download.01.org/0day-ci/archive/20230810/202308101758.4SiUa8Ee-lkp@intel.com/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce: (https://download.01.org/0day-ci/archive/20230810/202308101758.4SiUa8Ee-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308101758.4SiUa8Ee-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from mm/slub.c:21:
   In file included from mm/slab.h:236:
   In file included from include/linux/slub_def.h:10:
>> include/linux/kfence.h:58:47: error: 'char *' and 'void *' are not pointers to compatible types
           return unlikely((unsigned long)((char *)addr - __kfence_pool) < KFENCE_POOL_SIZE && __kfence_pool);
                                           ~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
   include/linux/compiler.h:77:42: note: expanded from macro 'unlikely'
   # define unlikely(x)    __builtin_expect(!!(x), 0)
                                               ^
   1 error generated.


vim +58 include/linux/kfence.h

0ce20dd840897b Alexander Potapenko 2021-02-25  32  
0ce20dd840897b Alexander Potapenko 2021-02-25  33  /**
0ce20dd840897b Alexander Potapenko 2021-02-25  34   * is_kfence_address() - check if an address belongs to KFENCE pool
0ce20dd840897b Alexander Potapenko 2021-02-25  35   * @addr: address to check
0ce20dd840897b Alexander Potapenko 2021-02-25  36   *
0ce20dd840897b Alexander Potapenko 2021-02-25  37   * Return: true or false depending on whether the address is within the KFENCE
0ce20dd840897b Alexander Potapenko 2021-02-25  38   * object range.
0ce20dd840897b Alexander Potapenko 2021-02-25  39   *
0ce20dd840897b Alexander Potapenko 2021-02-25  40   * KFENCE objects live in a separate page range and are not to be intermixed
0ce20dd840897b Alexander Potapenko 2021-02-25  41   * with regular heap objects (e.g. KFENCE objects must never be added to the
0ce20dd840897b Alexander Potapenko 2021-02-25  42   * allocator freelists). Failing to do so may and will result in heap
0ce20dd840897b Alexander Potapenko 2021-02-25  43   * corruptions, therefore is_kfence_address() must be used to check whether
0ce20dd840897b Alexander Potapenko 2021-02-25  44   * an object requires specific handling.
0ce20dd840897b Alexander Potapenko 2021-02-25  45   *
0ce20dd840897b Alexander Potapenko 2021-02-25  46   * Note: This function may be used in fast-paths, and is performance critical.
0ce20dd840897b Alexander Potapenko 2021-02-25  47   * Future changes should take this into account; for instance, we want to avoid
0ce20dd840897b Alexander Potapenko 2021-02-25  48   * introducing another load and therefore need to keep KFENCE_POOL_SIZE a
0ce20dd840897b Alexander Potapenko 2021-02-25  49   * constant (until immediate patching support is added to the kernel).
0ce20dd840897b Alexander Potapenko 2021-02-25  50   */
0ce20dd840897b Alexander Potapenko 2021-02-25  51  static __always_inline bool is_kfence_address(const void *addr)
0ce20dd840897b Alexander Potapenko 2021-02-25  52  {
0ce20dd840897b Alexander Potapenko 2021-02-25  53  	/*
a7cb5d23eaea14 Marco Elver         2021-08-19  54  	 * The __kfence_pool != NULL check is required to deal with the case
a7cb5d23eaea14 Marco Elver         2021-08-19  55  	 * where __kfence_pool == NULL && addr < KFENCE_POOL_SIZE. Keep it in
a7cb5d23eaea14 Marco Elver         2021-08-19  56  	 * the slow-path after the range-check!
0ce20dd840897b Alexander Potapenko 2021-02-25  57  	 */
a7cb5d23eaea14 Marco Elver         2021-08-19 @58  	return unlikely((unsigned long)((char *)addr - __kfence_pool) < KFENCE_POOL_SIZE && __kfence_pool);
0ce20dd840897b Alexander Potapenko 2021-02-25  59  }
0ce20dd840897b Alexander Potapenko 2021-02-25  60  

:::::: The code at line 58 was first introduced by commit
:::::: a7cb5d23eaea148f8582229846f8dfff192f05c3 kfence: fix is_kfence_address() for addresses below KFENCE_POOL_SIZE

:::::: TO: Marco Elver <elver@google.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

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