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-Ad... 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/1e66afa09b0aa7d6db3122f0312e10d36f6f... 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 lkp@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

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