Re: [PATCH v1 2/3] mm: Fix benign off-by-one bugs

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

Hi Alejandro,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on kees/for-next/pstore kees/for-next/kspp linus/master linux/master v6.18-rc5 next-20251111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Alejandro-Colomar/array_size-h-Add-ARRAY_END/20251110-075203
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/87445e701574058b142e036c3b8a0f505086ab64.1758806023.git.alx%40kernel.org
patch subject: [PATCH v1 2/3] mm: Fix benign off-by-one bugs
config: arm64-randconfig-002-20251111 (https://download.01.org/0day-ci/archive/20251111/202511111838.DEnuGlic-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 11.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251111/202511111838.DEnuGlic-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/202511111838.DEnuGlic-lkp@intel.com/

All warnings (new ones prefixed by >>):

   mm/kfence/kfence_test.c: In function 'report_matches':
   mm/kfence/kfence_test.c:113:15: error: implicit declaration of function 'ENDOF' [-Werror=implicit-function-declaration]
     113 |         end = ENDOF(expect[0]);
         |               ^~~~~
>> mm/kfence/kfence_test.c:113:13: warning: assignment to 'const char *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
     113 |         end = ENDOF(expect[0]);
         |             ^
   mm/kfence/kfence_test.c:143:13: warning: assignment to 'const char *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
     143 |         end = ENDOF(expect[1]);
         |             ^
   cc1: some warnings being treated as errors


vim +113 mm/kfence/kfence_test.c

    94	
    95	/* Check observed report matches information in @r. */
    96	static bool report_matches(const struct expect_report *r)
    97	{
    98		unsigned long addr = (unsigned long)r->addr;
    99		bool ret = false;
   100		unsigned long flags;
   101		typeof(observed.lines) expect;
   102		const char *end;
   103		char *cur;
   104	
   105		/* Doubled-checked locking. */
   106		if (!report_available())
   107			return false;
   108	
   109		/* Generate expected report contents. */
   110	
   111		/* Title */
   112		cur = expect[0];
 > 113		end = ENDOF(expect[0]);
   114		switch (r->type) {
   115		case KFENCE_ERROR_OOB:
   116			cur += scnprintf(cur, end - cur, "BUG: KFENCE: out-of-bounds %s",
   117					 get_access_type(r));
   118			break;
   119		case KFENCE_ERROR_UAF:
   120			cur += scnprintf(cur, end - cur, "BUG: KFENCE: use-after-free %s",
   121					 get_access_type(r));
   122			break;
   123		case KFENCE_ERROR_CORRUPTION:
   124			cur += scnprintf(cur, end - cur, "BUG: KFENCE: memory corruption");
   125			break;
   126		case KFENCE_ERROR_INVALID:
   127			cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid %s",
   128					 get_access_type(r));
   129			break;
   130		case KFENCE_ERROR_INVALID_FREE:
   131			cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid free");
   132			break;
   133		}
   134	
   135		scnprintf(cur, end - cur, " in %pS", r->fn);
   136		/* The exact offset won't match, remove it; also strip module name. */
   137		cur = strchr(expect[0], '+');
   138		if (cur)
   139			*cur = '\0';
   140	
   141		/* Access information */
   142		cur = expect[1];
   143		end = ENDOF(expect[1]);
   144	
   145		switch (r->type) {
   146		case KFENCE_ERROR_OOB:
   147			cur += scnprintf(cur, end - cur, "Out-of-bounds %s at", get_access_type(r));
   148			addr = arch_kfence_test_address(addr);
   149			break;
   150		case KFENCE_ERROR_UAF:
   151			cur += scnprintf(cur, end - cur, "Use-after-free %s at", get_access_type(r));
   152			addr = arch_kfence_test_address(addr);
   153			break;
   154		case KFENCE_ERROR_CORRUPTION:
   155			cur += scnprintf(cur, end - cur, "Corrupted memory at");
   156			break;
   157		case KFENCE_ERROR_INVALID:
   158			cur += scnprintf(cur, end - cur, "Invalid %s at", get_access_type(r));
   159			addr = arch_kfence_test_address(addr);
   160			break;
   161		case KFENCE_ERROR_INVALID_FREE:
   162			cur += scnprintf(cur, end - cur, "Invalid free of");
   163			break;
   164		}
   165	
   166		cur += scnprintf(cur, end - cur, " 0x%p", (void *)addr);
   167	
   168		spin_lock_irqsave(&observed.lock, flags);
   169		if (!report_available())
   170			goto out; /* A new report is being captured. */
   171	
   172		/* Finally match expected output to what we actually observed. */
   173		ret = strstr(observed.lines[0], expect[0]) && strstr(observed.lines[1], expect[1]);
   174	out:
   175		spin_unlock_irqrestore(&observed.lock, flags);
   176		return ret;
   177	}
   178	

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