Hi Oleg, FYI, the error/warning still remains. tree: https://gitee.com/openeuler/kernel.git OLK-6.6 head: db988390007bce595dba0dfd782c610578e26d2d commit: 54bee36be952f18f6a9e8303822459e89daaa336 [1613/1613] sched/isolation: Fix boot crash when maxcpus < first housekeeping CPU config: x86_64-buildonly-randconfig-004-20241210 (https://download.01.org/0day-ci/archive/20241210/202412100312.eJPOmnjW-lkp@i...) compiler: gcc-12 (Debian 12.2.0-14) 12.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241210/202412100312.eJPOmnjW-lkp@i...) 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 <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202412100312.eJPOmnjW-lkp@intel.com/ All errors (new ones prefixed by >>): In file included from kernel/sched/build_utility.c:105: kernel/sched/isolation.c: In function 'housekeeping_setup':

...

kernel/sched/isolation.c:134:53: error: 'setup_max_cpus' undeclared (first use in this function) 134 | if (first_cpu >= nr_cpu_ids || first_cpu >= setup_max_cpus) { | ^~~~~~~~~~~~~~ kernel/sched/isolation.c:134:53: note: each undeclared identifier is reported only once for each function it appears in

vim +/setup_max_cpus +134 kernel/sched/isolation.c 108 109 static int __init housekeeping_setup(char *str, unsigned long flags) 110 { 111 cpumask_var_t non_housekeeping_mask, housekeeping_staging; 112 unsigned int first_cpu; 113 int err = 0; 114 115 if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) { 116 if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) { 117 pr_warn("Housekeeping: nohz unsupported." 118 " Build with CONFIG_NO_HZ_FULL\n"); 119 return 0; 120 } 121 } 122 123 alloc_bootmem_cpumask_var(&non_housekeeping_mask); 124 if (cpulist_parse(str, non_housekeeping_mask) < 0) { 125 pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n"); 126 goto free_non_housekeeping_mask; 127 } 128 129 alloc_bootmem_cpumask_var(&housekeeping_staging); 130 cpumask_andnot(housekeeping_staging, 131 cpu_possible_mask, non_housekeeping_mask); 132 133 first_cpu = cpumask_first_and(cpu_present_mask, housekeeping_staging);

134 if (first_cpu >= nr_cpu_ids || first_cpu >= setup_max_cpus) { 135 __cpumask_set_cpu(smp_processor_id(), housekeeping_staging); 136 __cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask); 137 if (!housekeeping.flags) { 138 pr_warn("Housekeeping: must include one present CPU, " 139 "using boot CPU:%d\n", smp_processor_id()); 140 } 141 } 142 143 if (cpumask_empty(non_housekeeping_mask)) 144 goto free_housekeeping_staging; 145 146 if (!housekeeping.flags) { 147 /* First setup call ("nohz_full=" or "isolcpus=") */ 148 enum hk_type type; 149 150 for_each_set_bit(type, &flags, HK_TYPE_MAX) 151 housekeeping_setup_type(type, housekeeping_staging); 152 } else { 153 /* Second setup call ("nohz_full=" after "isolcpus=" or the reverse) */ 154 enum hk_type type; 155 unsigned long iter_flags = flags & housekeeping.flags; 156 157 for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) { 158 if (!cpumask_equal(housekeeping_staging, 159 housekeeping.cpumasks[type])) { 160 pr_warn("Housekeeping: nohz_full= must match isolcpus=\n"); 161 goto free_housekeeping_staging; 162 } 163 } 164 165 iter_flags = flags & ~housekeeping.flags; 166 167 for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) 168 housekeeping_setup_type(type, housekeeping_staging); 169 } 170 171 if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) 172 tick_nohz_full_setup(non_housekeeping_mask); 173 174 housekeeping.flags |= flags; 175 err = 1; 176 177 free_housekeeping_staging: 178 free_bootmem_cpumask_var(housekeeping_staging); 179 free_non_housekeeping_mask: 180 free_bootmem_cpumask_var(non_housekeeping_mask); 181 182 return err; 183 } 184

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