Hi Tamir,

kernel test robot noticed the following build warnings:

url:    
https://github.com/intel-lab-lkp/linux/commits/Tamir-Duberstein/ww_mutex-convert-self-test-to-KUnit/20250211-000245
base:   a64dcfb451e254085a7daee5fe51bf22959d52d3
patch link:    
https://lore.kernel.org/r/20250210-ww_mutex-kunit-convert-v1-1-972f0201f71e%40gmail.com
patch subject: [PATCH] ww_mutex: convert self-test to KUnit
config: i386-randconfig-141-20250212 
(https://download.01.org/0day-ci/archive/20250212/202502121806.cs6r741y-...@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project 
ab51eccf88f5321e7c60591c5546b254b6afab99)

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 <l...@intel.com>
| Reported-by: Dan Carpenter <dan.carpen...@linaro.org>
| Closes: https://lore.kernel.org/r/202502121806.cs6r741y-...@intel.com/

smatch warnings:
kernel/locking/ww_mutex_kunit.c:238 test_abba_gen_params() warn: shift has 
higher precedence than mask
kernel/locking/ww_mutex_kunit.c:249 test_abba() warn: shift has higher 
precedence than mask

vim +238 kernel/locking/ww_mutex_kunit.c

70207686e492fb kernel/locking/test-ww_mutex.c  Chris Wilson      2016-12-01  
231  
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
232  static const void *test_abba_gen_params(const void *prev, char *desc)
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
233  {
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
234        static unsigned int storage;
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
235        const unsigned int *next = gen_range(&storage, 0b00, 0b11, prev);
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
236  
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
237        if (next != NULL) {
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10 
@238                const bool trylock = *next & 0b01 >> 0;
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
239                const bool resolve = *next & 0b10 >> 1;

The shifts here are weird...  A zero shift is strange but even the 1 shift
is odd.  The current code is equivalent to:

        const bool resolve = *next & (0b10 >> 1);

But changing it to:

        const bool resolve = (*next & 0b10) >> 1;

Doesn't make sense either...  Probably that makes less sense actually.
What are you trying to communicate with this code?

daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
240  
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
241                snprintf(desc, KUNIT_PARAM_DESC_SIZE, 
"trylock=%d,resolve=%d", trylock, resolve);
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
242        }
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
243        return next;
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
244  }
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
245  
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
246  static void test_abba(struct kunit *test)
70207686e492fb kernel/locking/test-ww_mutex.c  Chris Wilson      2016-12-01  
247  {
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
248        const unsigned int *param = test->param_value;
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10 
@249        const bool trylock = *param & 0b01 >> 0;
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
250        const bool resolve = *param & 0b10 >> 1;

Same.

70207686e492fb kernel/locking/test-ww_mutex.c  Chris Wilson      2016-12-01  
251        struct test_abba abba;
70207686e492fb kernel/locking/test-ww_mutex.c  Chris Wilson      2016-12-01  
252        struct ww_acquire_ctx ctx;
daf92a37bd1117 kernel/locking/ww_mutex_kunit.c Tamir Duberstein  2025-02-10  
253        int err;
70207686e492fb kernel/locking/test-ww_mutex.c  Chris Wilson      2016-12-01  
254  
70207686e492fb kernel/locking/test-ww_mutex.c  Chris Wilson      2016-12-01  
255        ww_mutex_init(&abba.a_mutex, &ww_class);
70207686e492fb kernel/locking/test-ww_mutex.c  Chris Wilson      2016-12-01  
256        ww_mutex_init(&abba.b_mutex, &ww_class);
70207686e492fb kernel/locking/test-ww_mutex.c  Chris Wilson      2016-12-01  
257        INIT_WORK_ONSTACK(&abba.work, test_abba_work);

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


Reply via email to