sched/deadline: Use online cpus for validating runtime

[ Upstream commit 14672f059d83f591afb2ee1fff56858efe055e5a ]

The ftrace selftest reported a failure because writing -1 to
sched_rt_runtime_us returns -EBUSY. This happens when the possible
CPUs are different from active CPUs.

Active CPUs are part of one root domain, while remaining CPUs are part
of def_root_domain. Since active cpumask is being used, this results in
cpus=0 when a non active CPUs is used in the loop.

Fix it by looping over the online CPUs instead for validating the
bandwidth calculations.

Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20250306052954.452005-2-sshegde@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index d91295d3059f7da7ff1182363e337ff6cc6713d5..6548bd90c5c3acc3e8b463ee5f3f460eb2fef639 100644 (file)
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2577,7 +2577,7 @@ int sched_dl_global_validate(void)
         * cycling on root_domains... Discussion on different/better
         * solutions is welcome!
         */
-       for_each_possible_cpu(cpu) {
+       for_each_online_cpu(cpu) {
                rcu_read_lock_sched();
                dl_b = dl_bw_of(cpu);
                cpus = dl_bw_cpus(cpu);