Re: [PATCH 2/3] kstrtox: add unit tests for memparse_safe()

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2024/1/2 12:03, Yujie Liu wrote:
> On Tue, Dec 26, 2023 at 06:07:40PM +1030, Qu Wenruo wrote:
>> On 2023/12/26 17:06, kernel test robot wrote:
>>> Hi Qu,
>>>
>>> kernel test robot noticed the following build warnings:
>>>
>>> [auto build test WARNING on kdave/for-next]
>>> [also build test WARNING on akpm-mm/mm-everything linus/master v6.7-rc7 next-20231222]
>>> [cannot apply to akpm-mm/mm-nonmm-unstable]
>>> [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/Qu-Wenruo/kstrtox-introduce-a-safer-version-of-memparse/20231225-151921
>>> base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
>>> patch link:    https://lore.kernel.org/r/56ea15d8b430f4fe3f8e55509ad0bc72b1d9356f.1703324146.git.wqu%40suse.com
>>> patch subject: [PATCH 2/3] kstrtox: add unit tests for memparse_safe()
>>> config: m68k-randconfig-r133-20231226 (https://download.01.org/0day-ci/archive/20231226/202312261423.zqIlU2hn-lkp@intel.com/config)
>>> compiler: m68k-linux-gcc (GCC) 13.2.0
>>> reproduce: (https://download.01.org/0day-ci/archive/20231226/202312261423.zqIlU2hn-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/202312261423.zqIlU2hn-lkp@intel.com/
>>>
>>> sparse warnings: (new ones prefixed by >>)
>>>>> lib/test-kstrtox.c:339:40: sparse: sparse: cast truncates bits from constant value (efefefef7a7a7a7a becomes 7a7a7a7a)
>>>      lib/test-kstrtox.c:351:39: sparse: sparse: cast truncates bits from constant value (efefefef7a7a7a7a becomes 7a7a7a7a)
>>
>> Any way to suppress the warning? As long as the constant value (u64) is
>> checked against the same truncated value (u32), the result should be fine.
>
> Hi Qu, we've suppressed this warning in the bot for the specific file
> lib/test-kstrtox.c, while keep it enabled for the rest. If there are
> similar warnings in other files that could be false positives, we will
> also suppress them later.

I'll update the pattern depending on the ULL size to avoid the warning.

Thanks,
Qu
>
> Thanks,
> Yujie
>
>>
>> I really want to make sure the pointer is not incorrectly updated in the
>> failure case.
>>
>> Thanks,
>> Qu
>>>
>>> vim +339 lib/test-kstrtox.c
>>>
>>>      275
>>>      276	/* Want to include "E" suffix for full coverage. */
>>>      277	#define MEMPARSE_TEST_SUFFIX	(MEMPARSE_SUFFIX_K | MEMPARSE_SUFFIX_M |\
>>>      278					 MEMPARSE_SUFFIX_G | MEMPARSE_SUFFIX_T |\
>>>      279					 MEMPARSE_SUFFIX_P | MEMPARSE_SUFFIX_E)
>>>      280
>>>      281	static void __init test_memparse_safe_fail(void)
>>>      282	{
>>>      283		struct memparse_test_fail {
>>>      284			const char *str;
>>>      285			/* Expected error number, either -EINVAL or -ERANGE. */
>>>      286			unsigned int expected_ret;
>>>      287		};
>>>      288		static const struct memparse_test_fail tests[] __initconst = {
>>>      289			/* No valid string can be found at all. */
>>>      290			{"", -EINVAL},
>>>      291			{"\n", -EINVAL},
>>>      292			{"\n0", -EINVAL},
>>>      293			{"+", -EINVAL},
>>>      294			{"-", -EINVAL},
>>>      295
>>>      296			/*
>>>      297			 * No support for any leading "+-" chars, even followed by a valid
>>>      298			 * number.
>>>      299			 */
>>>      300			{"-0", -EINVAL},
>>>      301			{"+0", -EINVAL},
>>>      302			{"-1", -EINVAL},
>>>      303			{"+1", -EINVAL},
>>>      304
>>>      305			/* Stray suffix would also be rejected. */
>>>      306			{"K", -EINVAL},
>>>      307			{"P", -EINVAL},
>>>      308
>>>      309			/* Overflow in the string itself*/
>>>      310			{"18446744073709551616", -ERANGE},
>>>      311			{"02000000000000000000000", -ERANGE},
>>>      312			{"0x10000000000000000",	-ERANGE},
>>>      313
>>>      314			/*
>>>      315			 * Good string but would overflow with suffix.
>>>      316			 *
>>>      317			 * Note, for "E" suffix, one should not use with hex, or "0x1E"
>>>      318			 * would be treated as 0x1e (30 in decimal), not 0x1 and "E" suffix.
>>>      319			 * Another reason "E" suffix is cursed.
>>>      320			 */
>>>      321			{"16E", -ERANGE},
>>>      322			{"020E", -ERANGE},
>>>      323			{"16384P", -ERANGE},
>>>      324			{"040000P", -ERANGE},
>>>      325			{"16777216T", -ERANGE},
>>>      326			{"0100000000T", -ERANGE},
>>>      327			{"17179869184G", -ERANGE},
>>>      328			{"0200000000000G", -ERANGE},
>>>      329			{"17592186044416M", -ERANGE},
>>>      330			{"0400000000000000M", -ERANGE},
>>>      331			{"18014398509481984K", -ERANGE},
>>>      332			{"01000000000000000000K", -ERANGE},
>>>      333		};
>>>      334		unsigned int i;
>>>      335
>>>      336		for_each_test(i, tests) {
>>>      337			const struct memparse_test_fail *t = &tests[i];
>>>      338			unsigned long long tmp = ULL_PATTERN;
>>>    > 339			char *retptr = (char *)ULL_PATTERN;
>>>      340			int ret;
>>>      341
>>>      342			ret = memparse_safe(t->str, MEMPARSE_TEST_SUFFIX, &tmp, &retptr);
>>>      343			if (ret != t->expected_ret) {
>>>      344				WARN(1, "str '%s', expected ret %d got %d\n", t->str,
>>>      345				     t->expected_ret, ret);
>>>      346				continue;
>>>      347			}
>>>      348			if (tmp != ULL_PATTERN)
>>>      349				WARN(1, "str '%s' failed as expected, but result got modified",
>>>      350				     t->str);
>>>      351			if (retptr != (char *)ULL_PATTERN)
>>>      352				WARN(1, "str '%s' failed as expected, but pointer got modified",
>>>      353				     t->str);
>>>      354		}
>>>      355	}
>>>      356
>>>
>>
>