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Commit 413de336 authored by Paolo Valente's avatar Paolo Valente Committed by Razziell
Browse files

block/bfq: use pointer entity->sched_data only if set 



In the function __bfq_deactivate_entity, the pointer
entity->sched_data could happen to be used before being properly
initialized. This led to a NULL pointer dereference. This commit fixes
this bug by just using this pointer only where it is safe to do so.

Change-Id: I6b0f4e0182f71fb7e17af51f578b9a9109edd736
Reported-by: default avatarTom Harrison <l12436.tw@gmail.com>
Tested-by: default avatarTom Harrison <l12436.tw@gmail.com>
Signed-off-by: default avatarPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: default avatarFAROVITUS <farovitus@gmail.com>
Signed-off-by: default avatarAlbert I <krascgq@outlook.co.id>
parent 88a4d549

block/bfq-sched.c

+12 −3
Original line number Diff line number Diff line
@@ -1280,14 +1280,23 @@ static bool __bfq_deactivate_entity(struct bfq_entity *entity, 
				    bool ins_into_idle_tree)

{

	struct bfq_sched_data *sd = entity->sched_data;

	struct bfq_service_tree *st = bfq_entity_service_tree(entity);

	bool is_in_service = entity == sd->in_service_entity;

	struct bfq_service_tree *st;

	bool is_in_service;



	if (!entity->on_st) { /* entity never activated, or already inactive */

		BUG_ON(entity == entity->sched_data->in_service_entity);

		BUG_ON(sd && entity == sd->in_service_entity);

		return false;

	}



	/*

	 * If we get here, then entity is active, which implies that

	 * bfq_group_set_parent has already been invoked for the group

	 * represented by entity. Therefore, the field

	 * entity->sched_data has been set, and we can safely use it.

	 */

	st = bfq_entity_service_tree(entity);

	is_in_service = entity == sd->in_service_entity;



	BUG_ON(is_in_service && entity->tree && entity->tree != &st->active);



	if (is_in_service)