Messages in this thread | ![/](/images/icornerl.gif) | | From | Oleg Nesterov <> | Date | Thu, 2 May 2024 04:49:36 -0400 | Subject | Re: kernel/sched/isolation.c:143 housekeeping_setup() warn: always true condition '(first_cpu >= 0) => (0-u32max >= 0)' |
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Hello,
I am on PTO till May 9 without my working laptop, can't even read the source code. I'll return to this when I'm back. CONFIG_SMP=n I guess.
On 04/30, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > head: 98369dccd2f8e16bf4c6621053af7aa4821dcf8e > commit: 257bf89d84121280904800acd25cc2c444c717ae sched/isolation: Fix boot crash when maxcpus < first housekeeping CPU > date: 2 days ago > config: xtensa-randconfig-r081-20240429 (https://download.01.org/0day-ci/archive/20240430/202404300915.WNvfwBz3-lkp@intel.com/config) > compiler: xtensa-linux-gcc (GCC) 13.2.0 > > 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/202404300915.WNvfwBz3-lkp@intel.com/ > > New smatch warnings: > kernel/sched/isolation.c:143 housekeeping_setup() warn: always true condition '(first_cpu >= 0) => (0-u32max >= 0)' > > Old smatch warnings: > arch/xtensa/include/asm/thread_info.h:97 current_thread_info() warn: inconsistent indenting > > vim +143 kernel/sched/isolation.c > > 117 > 118 static int __init housekeeping_setup(char *str, unsigned long flags) > 119 { > 120 cpumask_var_t non_housekeeping_mask, housekeeping_staging; > 121 unsigned int first_cpu; > 122 int err = 0; > 123 > 124 if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) { > 125 if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) { > 126 pr_warn("Housekeeping: nohz unsupported." > 127 " Build with CONFIG_NO_HZ_FULL\n"); > 128 return 0; > 129 } > 130 } > 131 > 132 alloc_bootmem_cpumask_var(&non_housekeeping_mask); > 133 if (cpulist_parse(str, non_housekeeping_mask) < 0) { > 134 pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n"); > 135 goto free_non_housekeeping_mask; > 136 } > 137 > 138 alloc_bootmem_cpumask_var(&housekeeping_staging); > 139 cpumask_andnot(housekeeping_staging, > 140 cpu_possible_mask, non_housekeeping_mask); > 141 > 142 first_cpu = cpumask_first_and(cpu_present_mask, housekeeping_staging); > > 143 if (first_cpu >= nr_cpu_ids || first_cpu >= setup_max_cpus) { > 144 __cpumask_set_cpu(smp_processor_id(), housekeeping_staging); > 145 __cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask); > 146 if (!housekeeping.flags) { > 147 pr_warn("Housekeeping: must include one present CPU, " > 148 "using boot CPU:%d\n", smp_processor_id()); > 149 } > 150 } > 151 > 152 if (cpumask_empty(non_housekeeping_mask)) > 153 goto free_housekeeping_staging; > 154 > 155 if (!housekeeping.flags) { > 156 /* First setup call ("nohz_full=" or "isolcpus=") */ > 157 enum hk_type type; > 158 > 159 for_each_set_bit(type, &flags, HK_TYPE_MAX) > 160 housekeeping_setup_type(type, housekeeping_staging); > 161 } else { > 162 /* Second setup call ("nohz_full=" after "isolcpus=" or the reverse) */ > 163 enum hk_type type; > 164 unsigned long iter_flags = flags & housekeeping.flags; > 165 > 166 for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) { > 167 if (!cpumask_equal(housekeeping_staging, > 168 housekeeping.cpumasks[type])) { > 169 pr_warn("Housekeeping: nohz_full= must match isolcpus=\n"); > 170 goto free_housekeeping_staging; > 171 } > 172 } > 173 > 174 iter_flags = flags & ~housekeeping.flags; > 175 > 176 for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) > 177 housekeeping_setup_type(type, housekeeping_staging); > 178 } > 179 > 180 if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) > 181 tick_nohz_full_setup(non_housekeeping_mask); > 182 > 183 housekeeping.flags |= flags; > 184 err = 1; > 185 > 186 free_housekeeping_staging: > 187 free_bootmem_cpumask_var(housekeeping_staging); > 188 free_non_housekeeping_mask: > 189 free_bootmem_cpumask_var(non_housekeeping_mask); > 190 > 191 return err; > 192 } > 193 > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki >
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