kernel/sched/fair.c:9070 select_slice_cpu() warn: missing error code? 'cpu'

kernel/sched/fair.c:9070 select_slice_cpu() warn: missing error code? 'cpu'

[kernel test robot]

Unfiltered warning: this smatch report is sent as-is and has not been
reviewed for false positives, so please treat it with due skepticism.

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Vincent Guittot <vincent.guittot@linaro.org>
CC: 0day robot <lkp@intel.com>

tree:   https://github.com/intel-lab-lkp/linux/commits/Christian-Loehle/sched-eevdf-Cap-protection-when-current-has-the-shortest-slice/20260930-094737
head:   36883d29d7f46d450252ebe303f37131e2b837d2
commit: 8f8df1b98a5a60901a80f3f74b1c9ada4513f095 sched/eevdf: Add min slice check when selecting CPU
date:   2 weeks ago
:::::: branch date: 5 days ago
:::::: commit date: 2 weeks ago
config: arm-randconfig-r2201-20261005 (https://download.01.org/0day-ci/archive/20261005/202610051657.edNCMGy5-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project dbeca9a3a3ba0b46471efb339b0ea8f2194f6f68)
smatch: v0.5.0-9187-g5189e3fb

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>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202610051657.edNCMGy5-lkp@intel.com/

smatch warnings:
kernel/sched/fair.c:9070 select_slice_cpu() warn: missing error code? 'cpu'

vim +/cpu +9070 kernel/sched/fair.c

b4c9c9f15649c9 Vincent Guittot 2020-10-29  9025  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9026  static int select_slice_cpu(struct task_struct *p, struct sched_domain *sd, int target)
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9027  {
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9028  	unsigned long task_util, util_min, util_max;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9029  	int cpu, nr = INT_MAX;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9030  	u64 slice = p->se.slice;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9031  	struct cpumask *cpus;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9032  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9033  	if (sched_feat(SIS_UTIL) && sd->shared) {
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9034  		/*
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9035  		 * Same nr_idle_scan hint as select_idle_cpu(), nr only limits
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9036  		 * the scan when not preferring an idle core.
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9037  		 */
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9038  		nr = READ_ONCE(sd->shared->nr_idle_scan) + 1;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9039  		/* overloaded domain is unlikely to have idle cpu/core */
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9040  		if (nr == 1)
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9041  			return -1;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9042  	}
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9043  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9044  	cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9045  	cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9046  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9047  	if (sched_asym_cpucap_active()) {
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9048  		task_util = task_util_est(p);
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9049  		util_min = uclamp_eff_value(p, UCLAMP_MIN);
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9050  		util_max = uclamp_eff_value(p, UCLAMP_MAX);
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9051  	}
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9052  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9053  	/* Those CPUs have been tested not being idle and fiting */
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9054  	for_each_cpu_wrap(cpu, cpus, target) {
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9055  		/*
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9056  		 * Stop when the nr_idle_scan is exhausted (mirrors
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9057  		 * select_idle_cpu() logic).
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9058  		 */
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9059  		if (--nr <= 0)
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9060  			return -1;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9061  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9062  		if (slice >= get_rq_min_slice(cpu_rq(cpu)))
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9063  			continue;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9064  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9065  		if (sched_asym_cpucap_active()) {
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9066  			int fits = util_fits_cpu(task_util, util_min, util_max, cpu);
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9067  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9068  			/* Perfect fit: capacity satisfies util + uclamp */
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9069  			if (fits > 0)
8f8df1b98a5a60 Vincent Guittot 2026-09-21 @9070  				return cpu;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9071  		} else {
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9072  			return cpu;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9073  		}
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9074  	}
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9075  
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9076  	return -1;
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9077  }
8f8df1b98a5a60 Vincent Guittot 2026-09-21  9078  

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