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> > + !task_is_blocked(prev) || > > + !scx_allow_proxy_exec(prev)); > > switch_count = &prev->nvcsw; > > } > > > > diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c > > index c48d043dbe58f..8ffbf857acd51 100644 > > --- a/kernel/sched/ext/ext.c > > +++ b/kernel/sched/ext/ext.c > > @@ -23,6 +23,14 @@ > > > > DEFINE_RAW_SPINLOCK(scx_sched_lock); > > > > +bool scx_allow_proxy_exec(const struct task_struct *p) > > +{ > > + if (!task_on_scx(p)) > > + return true; > > + > > + return scx_task_sched(p)->ops.flags & SCX_OPS_ENQ_BLOCKED; > > +} > > + > > What happens when we switch in a a sched-ext scheduler that > doesn't support proxy? > > There would be a bunch proxy donors already preset at the time of the > scheduler loading but I don't see anything in the enable path that > would take care of those tasks by blocking them completely. > > Is it handled elsewhere? Good catch! It's not currently handled, a proxy donor that blocked before sched_ext was enabled can remain queued after being transferred to a scheduler that doesn't have SCX_OPS_ENQ_BLOCKED. We should probably deactivate existing blocked donors while switching them to a scheduler without proxy support. I'll fix this in the next version and add this case to the kselftest. Thanks, -Andrea