> Il giorno 27 nov 2021, alle ore 11:11, Yu Kuai <yukuai3@xxxxxxxxxx> ha scritto:
>
> Prevent null-ptr-deref after counting root group into
> 'num_groups_with_pending_reqs'.
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> ---
> block/bfq-iosched.c | 2 +-
> block/bfq-wf2q.c | 17 +++++++++++++----
> 2 files changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
> index 3262d062e21f..47722f931ee3 100644
> --- a/block/bfq-iosched.c
> +++ b/block/bfq-iosched.c
> @@ -864,7 +864,7 @@ void bfq_weights_tree_remove(struct bfq_data *bfqd,
> for_each_entity(entity) {
> struct bfq_sched_data *sd = entity->my_sched_data;
>
> - if (sd->next_in_service || sd->in_service_entity) {
> + if (sd && (sd->next_in_service || sd->in_service_entity)) {
Explain with some comment this additional check.
Paolo
> /*
> * entity is still active, because either
> * next_in_service or in_service_entity is not
> diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
> index 67e32481e455..6693765ff3a0 100644
> --- a/block/bfq-wf2q.c
> +++ b/block/bfq-wf2q.c
> @@ -965,6 +965,13 @@ static void __bfq_activate_entity(struct bfq_entity *entity,
> bool backshifted = false;
> unsigned long long min_vstart;
>
> + if (is_root_entity(entity))
> +#ifdef CONFIG_BFQ_GROUP_IOSCHED
> + goto update;
> +#else
> + return;
> +#endif
> +
> /* See comments on bfq_fqq_update_budg_for_activation */
> if (non_blocking_wait_rq && bfq_gt(st->vtime, entity->finish)) {
> backshifted = true;
> @@ -999,7 +1006,10 @@ static void __bfq_activate_entity(struct bfq_entity *entity,
> entity->on_st_or_in_serv = true;
> }
>
> + bfq_update_fin_time_enqueue(entity, st, backshifted);
> +
> #ifdef CONFIG_BFQ_GROUP_IOSCHED
> +update:
> if (!bfq_entity_to_bfqq(entity)) { /* bfq_group */
> struct bfq_group *bfqg =
> container_of(entity, struct bfq_group, entity);
> @@ -1011,8 +1021,6 @@ static void __bfq_activate_entity(struct bfq_entity *entity,
> }
> }
> #endif
> -
> - bfq_update_fin_time_enqueue(entity, st, backshifted);
> }
>
> /**
> @@ -1102,7 +1110,8 @@ static void __bfq_activate_requeue_entity(struct bfq_entity *entity,
> {
> struct bfq_service_tree *st = bfq_entity_service_tree(entity);
>
> - if (sd->in_service_entity == entity || entity->tree == &st->active)
> + if (sd && (sd->in_service_entity == entity ||
> + entity->tree == &st->active))
> /*
> * in service or already queued on the active tree,
> * requeue or reposition
> @@ -1140,7 +1149,7 @@ static void bfq_activate_requeue_entity(struct bfq_entity *entity,
> sd = entity->sched_data;
> __bfq_activate_requeue_entity(entity, sd, non_blocking_wait_rq);
>
> - if (!bfq_update_next_in_service(sd, entity, expiration) &&
> + if (sd && !bfq_update_next_in_service(sd, entity, expiration) &&
> !requeue)
> break;
> }
> --
> 2.31.1
>
