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-rw-r--r--tools/testing/selftests/sched_ext/numa.bpf.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/tools/testing/selftests/sched_ext/numa.bpf.c b/tools/testing/selftests/sched_ext/numa.bpf.c
index 78cc49a7f9a6..6b4515c28aa0 100644
--- a/tools/testing/selftests/sched_ext/numa.bpf.c
+++ b/tools/testing/selftests/sched_ext/numa.bpf.c
@@ -34,7 +34,8 @@ static bool is_cpu_idle(s32 cpu, int node)
s32 BPF_STRUCT_OPS(numa_select_cpu,
struct task_struct *p, s32 prev_cpu, u64 wake_flags)
{
- int node = __COMPAT_scx_bpf_cpu_node(scx_bpf_task_cpu(p));
+ s32 task_cpu = scx_bpf_task_cpu(p);
+ int node = __COMPAT_scx_bpf_cpu_node(task_cpu);
s32 cpu;
/*
@@ -48,6 +49,16 @@ s32 BPF_STRUCT_OPS(numa_select_cpu,
cpu = __COMPAT_scx_bpf_pick_any_cpu_node(p->cpus_ptr, node,
__COMPAT_SCX_PICK_IDLE_IN_NODE);
+ /*
+ * @task_cpu may be outside of p->cpus_ptr if @p's affinity
+ * changed while it was sleeping. This means it's possible for
+ * p->cpus_ptr to not include any CPUs from @node.
+ * If we failed to find a cpu in @node, check if @task_cpu
+ * is outside of p->cpus_ptr and just return @prev_cpu if it is.
+ */
+ if (cpu < 0 && !bpf_cpumask_test_cpu(task_cpu, p->cpus_ptr))
+ return prev_cpu;
+
if (is_cpu_idle(cpu, node))
scx_bpf_error("CPU %d should be marked as busy", cpu);