[PATCH] kernel/locking: Add context to ww_mutex_trylock.
kernel test robot
yujie.liu at intel.com
Tue Sep 14 03:49:46 UTC 2021
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 <lkp at 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
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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