Re: [PATCH] ww_mutex: convert self-test to KUnit
From: Dan Carpenter
Date: Wed Feb 12 2025 - 06:53:43 EST
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-lkp@xxxxxxxxx/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 <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202502121806.CS6r741y-lkp@xxxxxxxxx/
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);
--
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