CC: l...@lists.linux.dev CC: kbuild-...@lists.01.org BCC: l...@intel.com CC: linux-ker...@vger.kernel.org TO: Thomas Gleixner <t...@linutronix.de> CC: Ingo Molnar <mi...@kernel.org> CC: "Peter Zijlstra (Intel)" <pet...@infradead.org>
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 551acdc3c3d2b6bc97f11e31dcf960bc36343bfc commit: 531ae4b06a737ed5539cd75dc6f6b9a28f900bba locking/rtmutex: Split API from implementation date: 7 months ago :::::: branch date: 9 hours ago :::::: commit date: 7 months ago config: riscv-randconfig-c006-20220317 (https://download.01.org/0day-ci/archive/20220318/202203181309.e0l1dzxg-...@intel.com/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project a6ec1e3d798f8eab43fb3a91028c6ab04e115fcb) 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/torvalds/linux.git/commit/?id=531ae4b06a737ed5539cd75dc6f6b9a28f900bba git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 531ae4b06a737ed5539cd75dc6f6b9a28f900bba # save the config file to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 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 >>) ^ ~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:37:6: note: Assuming 'dividend_size' is not equal to 0 if (!dividend_size) ^~~~~~~~~~~~~~ lib/mpi/mpih-div.c:37:2: note: Taking false branch if (!dividend_size) ^ lib/mpi/mpih-div.c:49:4: note: Left side of '&&' is false && (UDIV_TIME - (2 * UMUL_TIME + 6)) * dividend_size > UDIV_TIME) { ^ lib/mpi/mpih-div.c:122:3: note: Taking true branch if (UDIV_NEEDS_NORMALIZATION) { ^ lib/mpi/mpih-div.c:125:26: note: Calling 'count_leading_zeros' normalization_steps = count_leading_zeros(divisor_limb); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/count_zeros.h:25:2: note: Taking true branch if (sizeof(x) == 4) ^ include/linux/count_zeros.h:26:3: note: Returning the value 32, which participates in a condition later return BITS_PER_LONG - fls(x); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/count_zeros.h:26:3: note: Returning the value 32 return BITS_PER_LONG - fls(x); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:125:26: note: Returning from 'count_leading_zeros' normalization_steps = count_leading_zeros(divisor_limb); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:125:4: note: The value 32 is assigned to 'normalization_steps' normalization_steps = count_leading_zeros(divisor_limb); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:126:8: note: 'normalization_steps' is 32 if (normalization_steps) { ^~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:126:4: note: Taking true branch if (normalization_steps) { ^ lib/mpi/mpih-div.c:127:18: note: Assigned value is garbage or undefined divisor_limb <<= normalization_steps; ^ ~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:202:12: warning: Division by zero [clang-analyzer-core.DivideZero] return 1 / dsize; ~~^~~~~~~ lib/mpi/mpih-div.c:194:2: note: Control jumps to 'case 0:' at line 195 switch (dsize) { ^ lib/mpi/mpih-div.c:202:12: note: Division by zero return 1 / dsize; ~~^~~~~~~ lib/mpi/mpih-div.c:475:18: warning: Assigned value is garbage or undefined [clang-analyzer-core.uninitialized.Assign] divisor_limb <<= normalization_steps; ^ ~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:387:6: note: Assuming 'dividend_size' is not equal to 0 if (!dividend_size) ^~~~~~~~~~~~~~ lib/mpi/mpih-div.c:387:2: note: Taking false branch if (!dividend_size) ^ lib/mpi/mpih-div.c:399:4: note: Left side of '&&' is false && (UDIV_TIME - (2 * UMUL_TIME + 6)) * dividend_size > UDIV_TIME) { ^ lib/mpi/mpih-div.c:470:3: note: Taking true branch if (UDIV_NEEDS_NORMALIZATION) { ^ lib/mpi/mpih-div.c:473:26: note: Calling 'count_leading_zeros' normalization_steps = count_leading_zeros(divisor_limb); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/count_zeros.h:25:2: note: Taking true branch if (sizeof(x) == 4) ^ include/linux/count_zeros.h:26:3: note: Returning the value 32, which participates in a condition later return BITS_PER_LONG - fls(x); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/count_zeros.h:26:3: note: Returning the value 32 return BITS_PER_LONG - fls(x); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:473:26: note: Returning from 'count_leading_zeros' normalization_steps = count_leading_zeros(divisor_limb); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:473:4: note: The value 32 is assigned to 'normalization_steps' normalization_steps = count_leading_zeros(divisor_limb); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:474:8: note: 'normalization_steps' is 32 if (normalization_steps) { ^~~~~~~~~~~~~~~~~~~ lib/mpi/mpih-div.c:474:4: note: Taking true branch if (normalization_steps) { ^ lib/mpi/mpih-div.c:475:18: note: Assigned value is garbage or undefined divisor_limb <<= normalization_steps; ^ ~~~~~~~~~~~~~~~~~~~ Suppressed 6 warnings (6 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 6 warnings generated. Suppressed 6 warnings (6 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 2 warnings generated. Suppressed 2 warnings (2 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 7 warnings generated. >> arch/riscv/include/asm/spinlock.h:24:2: warning: Dereference of null pointer >> [clang-analyzer-core.NullDereference] smp_store_release(&lock->lock, 0); ^ include/asm-generic/barrier.h:138:33: note: expanded from macro 'smp_store_release' #define smp_store_release(p, v) __smp_store_release(p, v) ^ arch/riscv/include/asm/barrier.h:34:2: note: expanded from macro '__smp_store_release' WRITE_ONCE(*p, v); \ ^ include/asm-generic/rwonce.h:61:2: note: expanded from macro 'WRITE_ONCE' __WRITE_ONCE(x, val); \ ^ include/asm-generic/rwonce.h:55:30: note: expanded from macro '__WRITE_ONCE' *(volatile typeof(x) *)&(x) = (val); \ ^ kernel/locking/rtmutex_api.c:419:2: note: Loop condition is false. Exiting loop raw_spin_lock_irqsave(&task->pi_lock, flags); ^ include/linux/spinlock.h:250:2: note: expanded from macro 'raw_spin_lock_irqsave' do { \ ^ kernel/locking/rtmutex_api.c:422:6: note: Assuming 'waiter' is non-null if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) { ^~~~~~~ kernel/locking/rtmutex_api.c:422:6: note: Left side of '||' is false kernel/locking/rtmutex_api.c:422:2: note: Taking false branch if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) { ^ kernel/locking/rtmutex_api.c:427:2: note: Loop condition is false. Exiting loop raw_spin_unlock_irqrestore(&task->pi_lock, flags); ^ include/linux/spinlock.h:288:2: note: expanded from macro 'raw_spin_unlock_irqrestore' do { \ ^ kernel/locking/rtmutex_api.c:432:2: note: Calling 'rt_mutex_adjust_prio_chain' rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:466:6: note: Assuming the condition is false if (++depth > max_lock_depth) { ^~~~~~~~~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:466:2: note: Taking false branch if (++depth > max_lock_depth) { ^ kernel/locking/rtmutex.c:510:6: note: Assuming 'waiter' is non-null if (!waiter) ^~~~~~~ kernel/locking/rtmutex.c:510:2: note: Taking false branch if (!waiter) ^ kernel/locking/rtmutex.c:517:6: note: 'orig_waiter' is null if (orig_waiter && !rt_mutex_owner(orig_lock)) ^~~~~~~~~~~ kernel/locking/rtmutex.c:517:18: note: Left side of '&&' is false if (orig_waiter && !rt_mutex_owner(orig_lock)) ^ kernel/locking/rtmutex.c:529:6: note: Assuming 'next_lock' is equal to field 'lock' if (next_lock != waiter->lock) ^~~~~~~~~~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:529:2: note: Taking false branch if (next_lock != waiter->lock) ^ kernel/locking/rtmutex.c:537:6: note: 'top_waiter' is null if (top_waiter) { ^~~~~~~~~~ kernel/locking/rtmutex.c:537:2: note: Taking false branch if (top_waiter) { ^ kernel/locking/rtmutex.c:561:6: note: Calling 'rt_mutex_waiter_equal' if (rt_mutex_waiter_equal(waiter, task_to_waiter(task))) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:274:6: note: Assuming 'left->prio' is not equal to 'right->prio' if (left->prio != right->prio) ^~~~~~~~~~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:274:2: note: Taking true branch if (left->prio != right->prio) ^ kernel/locking/rtmutex.c:275:3: note: Returning without writing to 'left->lock' return 0; ^ kernel/locking/rtmutex.c:275:3: note: Returning zero, which participates in a condition later return 0; ^~~~~~~~ kernel/locking/rtmutex.c:561:6: note: Returning from 'rt_mutex_waiter_equal' if (rt_mutex_waiter_equal(waiter, task_to_waiter(task))) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:561:2: note: Taking false branch if (rt_mutex_waiter_equal(waiter, task_to_waiter(task))) { ^ kernel/locking/rtmutex.c:571:2: note: Value assigned to 'lock' lock = waiter->lock; ^~~~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:577:6: note: Assuming the condition is false if (!raw_spin_trylock(&lock->wait_lock)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:577:2: note: Taking false branch if (!raw_spin_trylock(&lock->wait_lock)) { ^ kernel/locking/rtmutex.c:592:6: note: Assuming 'lock' is equal to 'orig_lock' if (lock == orig_lock || rt_mutex_owner(lock) == top_task) { ^~~~~~~~~~~~~~~~~ kernel/locking/rtmutex.c:592:24: note: Left side of '||' is true vim +24 arch/riscv/include/asm/spinlock.h fab957c11efe2f Palmer Dabbelt 2017-07-10 21 fab957c11efe2f Palmer Dabbelt 2017-07-10 22 static inline void arch_spin_unlock(arch_spinlock_t *lock) fab957c11efe2f Palmer Dabbelt 2017-07-10 23 { 0123f4d76ca63b Andrea Parri 2018-03-09 @24 smp_store_release(&lock->lock, 0); fab957c11efe2f Palmer Dabbelt 2017-07-10 25 } fab957c11efe2f Palmer Dabbelt 2017-07-10 26 :::::: The code at line 24 was first introduced by commit :::::: 0123f4d76ca63b7b895f40089be0ce4809e392d8 riscv/spinlock: Strengthen implementations with fences :::::: TO: Andrea Parri <parri.and...@gmail.com> :::::: CC: Palmer Dabbelt <pal...@sifive.com> --- 0-DAY CI Kernel Test Service https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org _______________________________________________ kbuild mailing list -- kbuild@lists.01.org To unsubscribe send an email to kbuild-le...@lists.01.org
