Hi Martin, kernel test robot noticed the following build warnings:
[auto build test WARNING on trace/for-next] [also build test WARNING on linus/master v7.2-rc6 next-20260806] [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#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Martin-Weiss/trace_branch-use-per-cpu-counters-for-correct-incorrect-stats/20260806-093445 base: https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next patch link: https://lore.kernel.org/r/20260629095838.601926-1-Martin.weiss2410%40gmail.com patch subject: [PATCH] trace_branch: use per-cpu counters for correct/incorrect stats config: arm64-randconfig-r062-20260806 (https://download.01.org/0day-ci/archive/20260807/[email protected]/config) compiler: aarch64-linux-gcc (GCC) 13.4.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260807/[email protected]/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <[email protected]> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ All warnings (new ones prefixed by >>): kernel/trace/trace_branch.c: In function 'ftrace_likely_update': >> kernel/trace/trace_branch.c:198:6: warning: infinite recursion detected >> [-Winfinite-recursion] 198 | void ftrace_likely_update(struct ftrace_likely_data *f, int val, | ^~~~~~~~~~~~~~~~~~~~ In file included from include/linux/array_size.h:5, from include/linux/kernel.h:16, from include/linux/kallsyms.h:11, from kernel/trace/trace_branch.c:7: include/linux/compiler.h:33:25: note: recursive call 33 | ftrace_likely_update(&______f, ______r, \ | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 34 | expect, is_constant); \ | ~~~~~~~~~~~~~~~~~~~~ include/linux/compiler.h:68:10: note: in definition of macro '__trace_if_value' 68 | (cond) ? \ | ^~~~ include/linux/compiler.h:55:28: note: in expansion of macro '__trace_if_var' 55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) | ^~~~~~~~~~~~~~ include/linux/preempt.h:238:9: note: in expansion of macro 'if' 238 | if (unlikely(__preempt_count_dec_and_test())) \ | ^~ include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__' 47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) | ^~~~~~~~~~~~~~~~ include/linux/preempt.h:238:13: note: in expansion of macro 'unlikely' 238 | if (unlikely(__preempt_count_dec_and_test())) \ | ^~~~~~~~ arch/arm64/include/asm/percpu.h:160:9: note: in expansion of macro 'preempt_enable_notrace' 160 | preempt_enable_notrace(); \ | ^~~~~~~~~~~~~~~~~~~~~~ arch/arm64/include/asm/percpu.h:197:9: note: in expansion of macro '_pcp_protect' 197 | _pcp_protect(__percpu_add_case_64, pcp, val) | ^~~~~~~~~~~~ include/linux/percpu-defs.h:372:25: note: in expansion of macro 'this_cpu_add_8' 372 | case 8: stem##8(variable, __VA_ARGS__);break; \ | ^~~~ include/linux/percpu-defs.h:501:41: note: in expansion of macro '__pcpu_size_call' 501 | #define this_cpu_add(pcp, val) __pcpu_size_call(this_cpu_add_, pcp, val) | ^~~~~~~~~~~~~~~~ include/linux/percpu-defs.h:511:41: note: in expansion of macro 'this_cpu_add' 511 | #define this_cpu_inc(pcp) this_cpu_add(pcp, 1) | ^~~~~~~~~~~~ kernel/trace/trace_branch.c:218:17: note: in expansion of macro 'this_cpu_inc' 218 | this_cpu_inc(f->data.correct); | ^~~~~~~~~~~~ include/linux/compiler.h:33:25: note: recursive call 33 | ftrace_likely_update(&______f, ______r, \ | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 34 | expect, is_constant); \ | ~~~~~~~~~~~~~~~~~~~~ include/linux/compiler.h:68:10: note: in definition of macro '__trace_if_value' 68 | (cond) ? \ | ^~~~ include/linux/compiler.h:55:28: note: in expansion of macro '__trace_if_var' 55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) | ^~~~~~~~~~~~~~ include/linux/preempt.h:238:9: note: in expansion of macro 'if' 238 | if (unlikely(__preempt_count_dec_and_test())) \ | ^~ include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__' 47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x))) | ^~~~~~~~~~~~~~~~ include/linux/preempt.h:238:13: note: in expansion of macro 'unlikely' 238 | if (unlikely(__preempt_count_dec_and_test())) \ | ^~~~~~~~ arch/arm64/include/asm/percpu.h:160:9: note: in expansion of macro 'preempt_enable_notrace' 160 | preempt_enable_notrace(); \ | ^~~~~~~~~~~~~~~~~~~~~~ arch/arm64/include/asm/percpu.h:197:9: note: in expansion of macro '_pcp_protect' 197 | _pcp_protect(__percpu_add_case_64, pcp, val) | ^~~~~~~~~~~~ include/linux/percpu-defs.h:372:25: note: in expansion of macro 'this_cpu_add_8' 372 | case 8: stem##8(variable, __VA_ARGS__);break; \ | ^~~~ include/linux/percpu-defs.h:501:41: note: in expansion of macro '__pcpu_size_call' 501 | #define this_cpu_add(pcp, val) __pcpu_size_call(this_cpu_add_, pcp, val) | ^~~~~~~~~~~~~~~~ include/linux/percpu-defs.h:511:41: note: in expansion of macro 'this_cpu_add' 511 | #define this_cpu_inc(pcp) this_cpu_add(pcp, 1) | ^~~~~~~~~~~~ kernel/trace/trace_branch.c:220:17: note: in expansion of macro 'this_cpu_inc' 220 | this_cpu_inc(f->data.incorrect); | ^~~~~~~~~~~~ vim +198 kernel/trace/trace_branch.c 52f232cb720a7b kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 197 134e6a034cb004 kernel/trace/trace_branch.c Steven Rostedt (VMware 2017-01-19 @198) void ftrace_likely_update(struct ftrace_likely_data *f, int val, d45ae1f7041ac5 kernel/trace/trace_branch.c Steven Rostedt (VMware 2017-01-17 199) int expect, int is_constant) 1f0d69a9fc815d kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 200 { 4a6c91fbdef846 kernel/trace/trace_branch.c Peter Zijlstra 2019-03-07 201 unsigned long flags = user_access_save(); 4a6c91fbdef846 kernel/trace/trace_branch.c Peter Zijlstra 2019-03-07 202 d45ae1f7041ac5 kernel/trace/trace_branch.c Steven Rostedt (VMware 2017-01-17 203) /* A constant is always correct */ 134e6a034cb004 kernel/trace/trace_branch.c Steven Rostedt (VMware 2017-01-19 204) if (is_constant) { 134e6a034cb004 kernel/trace/trace_branch.c Steven Rostedt (VMware 2017-01-19 205) f->constant++; d45ae1f7041ac5 kernel/trace/trace_branch.c Steven Rostedt (VMware 2017-01-17 206) val = expect; 134e6a034cb004 kernel/trace/trace_branch.c Steven Rostedt (VMware 2017-01-19 207) } 52f232cb720a7b kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 208 /* 52f232cb720a7b kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 209 * I would love to have a trace point here instead, but the 52f232cb720a7b kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 210 * trace point code is so inundated with unlikely and likely 52f232cb720a7b kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 211 * conditions that the recursive nightmare that exists is too 52f232cb720a7b kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 212 * much to try to get working. At least for now. 52f232cb720a7b kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 213 */ 068f530b3f274d kernel/trace/trace_branch.c Steven Rostedt (VMware 2017-01-19 214) trace_likely_condition(f, val, expect); 52f232cb720a7b kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 215 a53c1587fa9e39 kernel/trace/trace_branch.c Martin Weiss 2026-06-29 216 /* use per-cpu counters to avoid contention */ 1f0d69a9fc815d kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 217 if (val == expect) a53c1587fa9e39 kernel/trace/trace_branch.c Martin Weiss 2026-06-29 218 this_cpu_inc(f->data.correct); 1f0d69a9fc815d kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 219 else a53c1587fa9e39 kernel/trace/trace_branch.c Martin Weiss 2026-06-29 220 this_cpu_inc(f->data.incorrect); 4a6c91fbdef846 kernel/trace/trace_branch.c Peter Zijlstra 2019-03-07 221 4a6c91fbdef846 kernel/trace/trace_branch.c Peter Zijlstra 2019-03-07 222 user_access_restore(flags); 1f0d69a9fc815d kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 223 } 1f0d69a9fc815d kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 224 EXPORT_SYMBOL(ftrace_likely_update); 1f0d69a9fc815d kernel/trace/trace_unlikely.c Steven Rostedt 2008-11-12 225 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
