diff options
| author | Tejun Heo <tj@kernel.org> | 2026-04-24 14:31:35 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-04-24 14:31:35 -1000 |
| commit | da2d81b4118a74e65d2335e221a38d665902a98c (patch) | |
| tree | a9200c1da08a6977a8c41f0872716898e1a67413 /kernel | |
| parent | 4fda9f0e7c950da4fe03cedeb2ac818edf5d03e9 (diff) | |
sched_ext: Skip tasks with stale task_rq in bypass_lb_cpu()
bypass_lb_cpu() transfers tasks between per-CPU bypass DSQs without
migrating them - task_cpu() only updates when the donee later consumes the
task via move_remote_task_to_local_dsq(). If the LB timer fires again before
consumption and the new DSQ becomes a donor, @p is still on the previous CPU
and task_rq(@p) != donor_rq. @p can't be moved without its own rq locked.
Skip such tasks.
Fixes: 95d1df610cdc ("sched_ext: Implement load balancer for bypass mode")
Cc: stable@vger.kernel.org # v6.19+
Reported-by: Chris Mason <clm@meta.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 68c67113204f..f8500ce37b22 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -5023,6 +5023,15 @@ resume: if (cpumask_empty(donee_mask)) break; + /* + * If an earlier pass placed @p on @donor_dsq from a different + * CPU and the donee hasn't consumed it yet, @p is still on the + * previous CPU and task_rq(@p) != @donor_rq. @p can't be moved + * without its rq locked. Skip. + */ + if (task_rq(p) != donor_rq) + continue; + donee = cpumask_any_and_distribute(donee_mask, p->cpus_ptr); if (donee >= nr_cpu_ids) continue; |