On Wed, Jan 20, 2021 at 06:53:33PM +0100, Peter Zijlstra wrote: > On Wed, Jan 20, 2021 at 06:45:16PM +0100, Peter Zijlstra wrote: > > On Mon, Jan 11, 2021 at 05:10:46PM +0000, [email protected] wrote: > > > @@ -475,6 +478,11 @@ cpuhp_set_state(struct cpuhp_cpu_state *st, enum > > > cpuhp_state target) > > > static inline void > > > cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state > > > prev_state) > > > { > > > + st->target = prev_state; > > > + > > > + if (st->rollback) > > > + return; > > > > I'm thinking that if we call rollback while already rollback we're hosed > > something fierce, no? > > > > That like going up, failing, going back down again, also failing, giving > > up in a fiery death. > > Ooh, is this a hack for _cpu_down(): > > ret = cpuhp_down_callbacks(cpu, st, target); > if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) { > cpuhp_reset_state(st, prev_state); > __cpuhp_kick_ap(st); > } > > Where cpuhp_down_callbacks() can already have called cpuhp_reset_state() ?
Yes, it is now possible that this function will be called twice during the rollback. Shall I avoid this and treat the case above differently ? i.e. "if we are here, state has already been reset, and we should only set st->target". -- Vincent
