[kbuild-all] Re: [PATCH 1/2] ext4: mballoc - prefetching for bitmaps

Hi Alex, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on ext4/dev] [also build test WARNING on v5.7-rc6 next-20200519] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Alex-Zhuravlev/ext4-mballoc-pref... base: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev config: microblaze-randconfig-r024-20200519 (attached as .config) compiler: microblaze-linux-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=microblaze If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): In file included from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from fs/ext4/ext4_jbd2.h:15, from fs/ext4/mballoc.c:12: fs/ext4/mballoc.c: In function 'ext4_mb_prefetch': fs/ext4/mballoc.c:2137:12: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] 2137 | BUG_ON(nr < 0); | ^ include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var' 58 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) | ^~~~ 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~ include/linux/compiler.h:48:24: note: in expansion of macro '__branch_check__' 48 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) | ^~~~~~~~~~~~~~~~ include/asm-generic/bug.h:62:36: note: in expansion of macro 'unlikely' 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~~~~~~~ fs/ext4/mballoc.c:2137:2: note: in expansion of macro 'BUG_ON' 2137 | BUG_ON(nr < 0); | ^~~~~~ fs/ext4/mballoc.c:2137:12: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] 2137 | BUG_ON(nr < 0); | ^ include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var' 58 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) | ^~~~ 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~ include/linux/compiler.h:48:24: note: in expansion of macro '__branch_check__' 48 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) | ^~~~~~~~~~~~~~~~ include/asm-generic/bug.h:62:36: note: in expansion of macro 'unlikely' 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~~~~~~~ fs/ext4/mballoc.c:2137:2: note: in expansion of macro 'BUG_ON' 2137 | BUG_ON(nr < 0); | ^~~~~~ fs/ext4/mballoc.c:2137:12: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] 2137 | BUG_ON(nr < 0); | ^ include/linux/compiler.h:58:61: note: in definition of macro '__trace_if_var' 58 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) | ^~~~ 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~ include/linux/compiler.h:48:24: note: in expansion of macro '__branch_check__' 48 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) | ^~~~~~~~~~~~~~~~ include/asm-generic/bug.h:62:36: note: in expansion of macro 'unlikely' 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~~~~~~~ fs/ext4/mballoc.c:2137:2: note: in expansion of macro 'BUG_ON' 2137 | BUG_ON(nr < 0); | ^~~~~~ fs/ext4/mballoc.c:2137:12: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] 2137 | BUG_ON(nr < 0); | ^ include/linux/compiler.h:58:61: note: in definition of macro '__trace_if_var' 58 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) | ^~~~ 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~ include/linux/compiler.h:48:24: note: in expansion of macro '__branch_check__' 48 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) | ^~~~~~~~~~~~~~~~ include/asm-generic/bug.h:62:36: note: in expansion of macro 'unlikely' 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~~~~~~~ fs/ext4/mballoc.c:2137:2: note: in expansion of macro 'BUG_ON' 2137 | BUG_ON(nr < 0); | ^~~~~~ fs/ext4/mballoc.c:2137:12: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] 2137 | BUG_ON(nr < 0); | ^ include/linux/compiler.h:69:3: note: in definition of macro '__trace_if_value' 69 | (cond) ? | ^~~~ include/linux/compiler.h:56:28: note: in expansion of macro '__trace_if_var' 56 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) | ^~~~~~~~~~~~~~ 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~ include/linux/compiler.h:48:24: note: in expansion of macro '__branch_check__' 48 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) | ^~~~~~~~~~~~~~~~ include/asm-generic/bug.h:62:36: note: in expansion of macro 'unlikely' 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~~~~~~~ fs/ext4/mballoc.c:2137:2: note: in expansion of macro 'BUG_ON' 2137 | BUG_ON(nr < 0); | ^~~~~~ fs/ext4/mballoc.c:2137:12: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] 2137 | BUG_ON(nr < 0); | ^ include/linux/compiler.h:69:3: note: in definition of macro '__trace_if_value' 69 | (cond) ? | ^~~~ include/linux/compiler.h:56:28: note: in expansion of macro '__trace_if_var' 56 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) | ^~~~~~~~~~~~~~ 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~ include/linux/compiler.h:48:24: note: in expansion of macro '__branch_check__' 48 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) | ^~~~~~~~~~~~~~~~ include/asm-generic/bug.h:62:36: note: in expansion of macro 'unlikely' 62 | #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) | ^~~~~~~~ fs/ext4/mballoc.c:2137:2: note: in expansion of macro 'BUG_ON' 2137 | BUG_ON(nr < 0); | ^~~~~~ vim +/if +62 include/asm-generic/bug.h ^1da177e4c3f41 Linus Torvalds 2005-04-16 60 ^1da177e4c3f41 Linus Torvalds 2005-04-16 61 #ifndef HAVE_ARCH_BUG_ON 2a41de48b81e61 Alexey Dobriyan 2007-07-17 @62 #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) ^1da177e4c3f41 Linus Torvalds 2005-04-16 63 #endif ^1da177e4c3f41 Linus Torvalds 2005-04-16 64 :::::: The code at line 62 was first introduced by commit :::::: 2a41de48b81e61fbe260ae5031ebcb6f935f35fb Fix sparse false positives re BUG_ON(ptr) :::::: TO: Alexey Dobriyan <adobriyan(a)sw.ru&gt; :::::: CC: Linus Torvalds <torvalds(a)woody.linux-foundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org