Date: Wed, 19 Jul 2023 13:36:38 +0800
From: kernel test robot <lkp@intel.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org
Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
	Linux Memory Management List <linux-mm@kvack.org>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Alexander Potapenko <glider@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH v1 1/1] kasan: Replace strreplace() with strchrnul()
Message-ID: <202307191350.tJh2PZdE-lkp@intel.com>
References: <20230628153342.53406-1-andriy.shevchenko@linux.intel.com>
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In-Reply-To: <20230628153342.53406-1-andriy.shevchenko@linux.intel.com>

Hi Andy,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on linus/master v6.5-rc2 next-20230718]
[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/Andy-Shevchenko/kasan-Replace-strreplace-with-strchrnul/20230628-233727
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20230628153342.53406-1-andriy.shevchenko%40linux.intel.com
patch subject: [PATCH v1 1/1] kasan: Replace strreplace() with strchrnul()
config: x86_64-randconfig-x001-20230718 (https://download.01.org/0day-ci/archive/20230719/202307191350.tJh2PZdE-lkp@intel.com/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce: (https://download.01.org/0day-ci/archive/20230719/202307191350.tJh2PZdE-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/202307191350.tJh2PZdE-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/kasan/report_generic.c:286:3: warning: variable 'p' is uninitialized when used here [-Wuninitialized]
                   p[strchrnul(token, ':') - token] = '\0';
                   ^
   mm/kasan/report_generic.c:267:10: note: initialize the variable 'p' to silence this warning
                   char *p;
                          ^
                           = NULL
   1 warning generated.


vim +/p +286 mm/kasan/report_generic.c

   242	
   243	static void print_decoded_frame_descr(const char *frame_descr)
   244	{
   245		/*
   246		 * We need to parse the following string:
   247		 *    "n alloc_1 alloc_2 ... alloc_n"
   248		 * where alloc_i looks like
   249		 *    "offset size len name"
   250		 * or "offset size len name:line".
   251		 */
   252	
   253		char token[64];
   254		unsigned long num_objects;
   255	
   256		if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
   257					  &num_objects))
   258			return;
   259	
   260		pr_err("\n");
   261		pr_err("This frame has %lu %s:\n", num_objects,
   262		       num_objects == 1 ? "object" : "objects");
   263	
   264		while (num_objects--) {
   265			unsigned long offset;
   266			unsigned long size;
   267			char *p;
   268	
   269			/* access offset */
   270			if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
   271						  &offset))
   272				return;
   273			/* access size */
   274			if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
   275						  &size))
   276				return;
   277			/* name length (unused) */
   278			if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL))
   279				return;
   280			/* object name */
   281			if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
   282						  NULL))
   283				return;
   284	
   285			/* Strip line number; without filename it's not very helpful. */
 > 286			p[strchrnul(token, ':') - token] = '\0';
   287	
   288			/* Finally, print object information. */
   289			pr_err(" [%lu, %lu) '%s'", offset, offset + size, token);
   290		}
   291	}
   292	

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