* [frederic-dynticks:rcu/dev 1/4] kernel/rcu/tree_nocb.h:1355:7: warning: variable '_count' is uninitialized when used here
@ 2023-03-22 3:57 kernel test robot
0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2023-03-22 3:57 UTC (permalink / raw)
To: Frederic Weisbecker; +Cc: llvm, oe-kbuild-all, fweisbec
tree: https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git rcu/dev
head: 7f7c396422722db9db601852664a30597a4fc7df
commit: 9c1b4fd66a0ce529b431385e86693cd81f194e85 [1/4] rcu/nocb: Protect lazy shrinker against concurrent (de-)offloading
config: riscv-randconfig-r001-20230320 (https://download.01.org/0day-ci/archive/20230322/202303221136.n0Fd8NZa-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
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
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git/commit/?id=9c1b4fd66a0ce529b431385e86693cd81f194e85
git remote add frederic-dynticks https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
git fetch --no-tags frederic-dynticks rcu/dev
git checkout 9c1b4fd66a0ce529b431385e86693cd81f194e85
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash kernel/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303221136.n0Fd8NZa-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from kernel/rcu/tree.c:4956:
>> kernel/rcu/tree_nocb.h:1355:7: warning: variable '_count' is uninitialized when used here [-Wuninitialized]
if (_count == 0)
^~~~~~
kernel/rcu/tree_nocb.h:1348:13: note: initialize the variable '_count' to silence this warning
int _count;
^
= 0
1 warning generated.
vim +/_count +1355 kernel/rcu/tree_nocb.h
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1331
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1332 static unsigned long
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1333 lazy_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1334 {
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1335 int cpu;
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1336 unsigned long flags;
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1337 unsigned long count = 0;
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1338
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1339 /*
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1340 * Protect against concurrent (de-)offloading. Otherwise nocb locking
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1341 * may be ignored or imbalanced.
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1342 */
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1343 mutex_lock(&rcu_state.barrier_mutex);
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1344
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1345 /* Snapshot count of all CPUs */
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1346 for_each_possible_cpu(cpu) {
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1347 struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1348 int _count;
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1349
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1350 if (!rcu_rdp_is_offloaded(rdp))
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1351 continue;
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1352
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1353 count = READ_ONCE(rdp->lazy_len);
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1354
c945b4da7a448a9 Vineeth Pillai 2022-10-16 @1355 if (_count == 0)
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1356 continue;
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1357
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1358 rcu_nocb_lock_irqsave(rdp, flags);
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1359 WRITE_ONCE(rdp->lazy_len, 0);
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1360 rcu_nocb_unlock_irqrestore(rdp, flags);
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1361 wake_nocb_gp(rdp, false);
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1362 sc->nr_to_scan -= _count;
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1363 count += _count;
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1364 if (sc->nr_to_scan <= 0)
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1365 break;
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1366 }
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1367
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1368 mutex_unlock(&rcu_state.barrier_mutex);
9c1b4fd66a0ce52 Frederic Weisbecker 2023-03-17 1369
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1370 return count ? count : SHRINK_STOP;
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1371 }
c945b4da7a448a9 Vineeth Pillai 2022-10-16 1372
:::::: The code at line 1355 was first introduced by commit
:::::: c945b4da7a448a9a56becc5a8745d942b2b83d3c rcu: Shrinker for lazy rcu
:::::: TO: Vineeth Pillai <vineeth@bitbyteword.org>
:::::: CC: Paul E. McKenney <paulmck@kernel.org>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
^ permalink raw reply [flat|nested] 2+ messages in thread
* [frederic-dynticks:rcu/dev 1/4] kernel/rcu/tree_nocb.h:1355:7: warning: variable '_count' is uninitialized when used here
@ 2023-03-22 3:47 kernel test robot
0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2023-03-22 3:47 UTC (permalink / raw)
To: Frederic Weisbecker; +Cc: llvm, oe-kbuild-all, fweisbec
tree: https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git rcu/dev
head: 7f7c396422722db9db601852664a30597a4fc7df
commit: 9c1b4fd66a0ce529b431385e86693cd81f194e85 [1/4] rcu/nocb: Protect lazy shrinker against concurrent (de-)offloading
config: riscv-randconfig-r016-20230319 (https://download.01.org/0day-ci/archive/20230322/202303221149.HHwYkAFu-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
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
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv-linux-gnu
# https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git/commit/?id=9c1b4fd66a0ce529b431385e86693cd81f194e85
git remote add frederic-dynticks https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
git fetch --no-tags frederic-dynticks rcu/dev
git checkout 9c1b4fd66a0ce529b431385e86693cd81f194e85
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash kernel/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303221149.HHwYkAFu-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from kernel/rcu/tree.c:4956:
>> kernel/rcu/tree_nocb.h:1355:7: warning: variable '_count' is uninitialized when used here [-Wuninitialized]
if (_count == 0)
^~~~~~
kernel/rcu/tree_nocb.h:1348:13: note: initialize the variable '_count' to silence this warning
int _count;
^
= 0
1 warning generated.
vim +/_count +1355 kernel/rcu/tree_nocb.h
c945b4da7a448a Vineeth Pillai 2022-10-16 1331
c945b4da7a448a Vineeth Pillai 2022-10-16 1332 static unsigned long
c945b4da7a448a Vineeth Pillai 2022-10-16 1333 lazy_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
c945b4da7a448a Vineeth Pillai 2022-10-16 1334 {
c945b4da7a448a Vineeth Pillai 2022-10-16 1335 int cpu;
c945b4da7a448a Vineeth Pillai 2022-10-16 1336 unsigned long flags;
c945b4da7a448a Vineeth Pillai 2022-10-16 1337 unsigned long count = 0;
c945b4da7a448a Vineeth Pillai 2022-10-16 1338
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1339 /*
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1340 * Protect against concurrent (de-)offloading. Otherwise nocb locking
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1341 * may be ignored or imbalanced.
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1342 */
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1343 mutex_lock(&rcu_state.barrier_mutex);
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1344
c945b4da7a448a Vineeth Pillai 2022-10-16 1345 /* Snapshot count of all CPUs */
c945b4da7a448a Vineeth Pillai 2022-10-16 1346 for_each_possible_cpu(cpu) {
c945b4da7a448a Vineeth Pillai 2022-10-16 1347 struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1348 int _count;
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1349
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1350 if (!rcu_rdp_is_offloaded(rdp))
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1351 continue;
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1352
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1353 count = READ_ONCE(rdp->lazy_len);
c945b4da7a448a Vineeth Pillai 2022-10-16 1354
c945b4da7a448a Vineeth Pillai 2022-10-16 @1355 if (_count == 0)
c945b4da7a448a Vineeth Pillai 2022-10-16 1356 continue;
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1357
c945b4da7a448a Vineeth Pillai 2022-10-16 1358 rcu_nocb_lock_irqsave(rdp, flags);
c945b4da7a448a Vineeth Pillai 2022-10-16 1359 WRITE_ONCE(rdp->lazy_len, 0);
c945b4da7a448a Vineeth Pillai 2022-10-16 1360 rcu_nocb_unlock_irqrestore(rdp, flags);
c945b4da7a448a Vineeth Pillai 2022-10-16 1361 wake_nocb_gp(rdp, false);
c945b4da7a448a Vineeth Pillai 2022-10-16 1362 sc->nr_to_scan -= _count;
c945b4da7a448a Vineeth Pillai 2022-10-16 1363 count += _count;
c945b4da7a448a Vineeth Pillai 2022-10-16 1364 if (sc->nr_to_scan <= 0)
c945b4da7a448a Vineeth Pillai 2022-10-16 1365 break;
c945b4da7a448a Vineeth Pillai 2022-10-16 1366 }
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1367
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1368 mutex_unlock(&rcu_state.barrier_mutex);
9c1b4fd66a0ce5 Frederic Weisbecker 2023-03-17 1369
c945b4da7a448a Vineeth Pillai 2022-10-16 1370 return count ? count : SHRINK_STOP;
c945b4da7a448a Vineeth Pillai 2022-10-16 1371 }
c945b4da7a448a Vineeth Pillai 2022-10-16 1372
:::::: The code at line 1355 was first introduced by commit
:::::: c945b4da7a448a9a56becc5a8745d942b2b83d3c rcu: Shrinker for lazy rcu
:::::: TO: Vineeth Pillai <vineeth@bitbyteword.org>
:::::: CC: Paul E. McKenney <paulmck@kernel.org>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
^ permalink raw reply [flat|nested] 2+ messages in thread
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