Hi Maarten,

I love your patch! Perhaps something to improve:

[auto build test WARNING on regulator/for-next]
[also build test WARNING on tegra-drm/drm/tegra/for-next v5.14]
[cannot apply to tip/locking/core linus/master next-20210909]
[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]

url:    
https://github.com/0day-ci/linux/commits/Maarten-Lankhorst/kernel-locking-Add-context-to-ww_mutex_trylock/20210907-212220
base:   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git 
for-next
:::::: branch date: 2 days ago
:::::: commit date: 2 days ago
config: x86_64-randconfig-c007-20210908 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 
9c476172b93367d2cb88d7d3f4b1b5b456fa6020)
reproduce (this is a W=1 build):
        wget 
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O 
~/bin/make.cross
        chmod +x ~/bin/make.cross
        # 
https://github.com/0day-ci/linux/commit/1e66afa09b0aa7d6db3122f0312e10d36f6fa217
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review 
Maarten-Lankhorst/kernel-locking-Add-context-to-ww_mutex_trylock/20210907-212220
        git checkout 1e66afa09b0aa7d6db3122f0312e10d36f6fa217
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 
clang-analyzer

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <l...@intel.com>


clang-analyzer warnings: (new ones prefixed by >>)

>> kernel/locking/test-ww_mutex.c:172:2: warning: Undefined or garbage value 
returned to caller [clang-analyzer-core.uninitialized.UndefReturn]
           return ret;
           ^
   kernel/locking/test-ww_mutex.c:639:8: note: Calling 'test_aa'
           ret = test_aa(true);
                 ^~~~~~~~~~~~~
   kernel/locking/test-ww_mutex.c:125:2: note: 'ret' declared without an 
initial value
           int ret;
           ^~~~~~~
   kernel/locking/test-ww_mutex.c:126:21: note: 'trylock' is true
           const char *from = trylock ? "trylock" : "lock";
                              ^~~~~~~
   kernel/locking/test-ww_mutex.c:126:21: note: '?' condition is true
   kernel/locking/test-ww_mutex.c:131:7: note: 'trylock' is true
           if (!trylock) {
                ^~~~~~~
   kernel/locking/test-ww_mutex.c:131:2: note: Taking false branch
           if (!trylock) {
           ^
   kernel/locking/test-ww_mutex.c:138:7: note: Assuming the condition is true
                   if (!ww_mutex_trylock(&mutex, &ctx)) {
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/locking/test-ww_mutex.c:138:3: note: Taking true branch
                   if (!ww_mutex_trylock(&mutex, &ctx)) {
                   ^
   kernel/locking/test-ww_mutex.c:140:4: note: Control jumps to line 171
                           goto out;
                           ^
   kernel/locking/test-ww_mutex.c:172:2: note: Undefined or garbage value 
returned to caller
           return ret;
           ^      ~~~

vim +172 kernel/locking/test-ww_mutex.c

f2a5fec17395f2 Chris Wilson      2016-12-01  120
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  121  static int test_aa(bool 
trylock)
c22fb3807fd0a3 Chris Wilson      2016-12-01  122  {
c22fb3807fd0a3 Chris Wilson      2016-12-01  123        struct ww_mutex mutex;
c22fb3807fd0a3 Chris Wilson      2016-12-01  124        struct ww_acquire_ctx 
ctx;
c22fb3807fd0a3 Chris Wilson      2016-12-01  125        int ret;
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  126        const char *from = trylock ? 
"trylock" : "lock";
c22fb3807fd0a3 Chris Wilson      2016-12-01  127
c22fb3807fd0a3 Chris Wilson      2016-12-01  128        ww_mutex_init(&mutex, 
&ww_class);
c22fb3807fd0a3 Chris Wilson      2016-12-01  129        ww_acquire_init(&ctx, 
&ww_class);
c22fb3807fd0a3 Chris Wilson      2016-12-01  130
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  131        if (!trylock) {
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  132                ret = 
ww_mutex_lock(&mutex, &ctx);
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  133                if (ret) {
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  134                        pr_err("%s: 
initial lock failed!\n", __func__);
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  135                        goto 
out;
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  136                }
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  137        } else {
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  138                if 
(!ww_mutex_trylock(&mutex, &ctx)) {
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  139                        pr_err("%s: 
initial trylock failed!\n", __func__);
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  140                        goto 
out;
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  141                }
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  142        }
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  143
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  144        if 
(ww_mutex_trylock(&mutex, NULL))  {
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  145                pr_err("%s: 
trylocked itself without context from %s!\n", __func__, from);
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  146                
ww_mutex_unlock(&mutex);
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  147                ret = -EINVAL;
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  148                goto out;
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  149        }
c22fb3807fd0a3 Chris Wilson      2016-12-01  150
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  151        if 
(ww_mutex_trylock(&mutex, &ctx))  {
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  152                pr_err("%s: 
trylocked itself with context from %s!\n", __func__, from);
c22fb3807fd0a3 Chris Wilson      2016-12-01  153                
ww_mutex_unlock(&mutex);
c22fb3807fd0a3 Chris Wilson      2016-12-01  154                ret = -EINVAL;
c22fb3807fd0a3 Chris Wilson      2016-12-01  155                goto out;
c22fb3807fd0a3 Chris Wilson      2016-12-01  156        }
c22fb3807fd0a3 Chris Wilson      2016-12-01  157
c22fb3807fd0a3 Chris Wilson      2016-12-01  158        ret = ww_mutex_lock(&mutex, 
&ctx);
c22fb3807fd0a3 Chris Wilson      2016-12-01  159        if (ret != -EALREADY) {
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  160                pr_err("%s: missed 
deadlock for recursing, ret=%d from %s\n",
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  161                       
__func__, ret, from);
c22fb3807fd0a3 Chris Wilson      2016-12-01  162                if (!ret)
c22fb3807fd0a3 Chris Wilson      2016-12-01  163                        
ww_mutex_unlock(&mutex);
c22fb3807fd0a3 Chris Wilson      2016-12-01  164                ret = -EINVAL;
c22fb3807fd0a3 Chris Wilson      2016-12-01  165                goto out;
c22fb3807fd0a3 Chris Wilson      2016-12-01  166        }
c22fb3807fd0a3 Chris Wilson      2016-12-01  167
1e66afa09b0aa7 Maarten Lankhorst 2021-09-07  168        ww_mutex_unlock(&mutex);
c22fb3807fd0a3 Chris Wilson      2016-12-01  169        ret = 0;
c22fb3807fd0a3 Chris Wilson      2016-12-01  170  out:
c22fb3807fd0a3 Chris Wilson      2016-12-01  171        ww_acquire_fini(&ctx);
c22fb3807fd0a3 Chris Wilson      2016-12-01 @172        return ret;
c22fb3807fd0a3 Chris Wilson      2016-12-01  173  }
c22fb3807fd0a3 Chris Wilson      2016-12-01  174

---
0-DAY CI Kernel Test Service, Intel Corporation
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