Hello Tejun Heo,
Commit 037df2a314a0 ("sched_ext: Add a central scheduler which makes
all scheduling decisions on one CPU") from Jun 18, 2024 (linux-next),
leads to the following Smatch static checker warning:
./tools/sched_ext/scx_central.bpf.c:205 ____central_dispatch()
error: we previously assumed 'gimme' could be null (see line 201)
./tools/sched_ext/scx_central.bpf.c
195
196 if (!scx_bpf_dispatch_nr_slots())
197 break;
198
199 /* central's gimme is never set */
200 gimme = ARRAY_ELEM_PTR(cpu_gimme_task, cpu, nr_cpu_ids);
201 if (gimme && !*gimme)
^^^^^
If gimme is NULL
202 continue;
203
204 if (dispatch_to_cpu(cpu))
--> 205 *gimme = false;
^^^^^^
then this could be an issue?
206 }
207
208 /*
209 * Retry if we ran out of dispatch buffer slots as we might have
210 * skipped some CPUs and also need to dispatch for self. The ext
211 * core automatically retries if the local dsq is empty but we
212 * can't rely on that as we're dispatching for other CPUs too.
213 * Kick self explicitly to retry.
214 */
215 if (!scx_bpf_dispatch_nr_slots()) {
regards,
dan carpenter
