Commit 8f48894f authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Add debug check to task_of() 



A frequent mistake appears to be to call task_of() on a
scheduler entity that is not actually a task, which can result
in a wild pointer.

Add a check to catch these mistakes.

Suggested-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 00aec93d

kernel/sched_fair.c

+14 −6
Original line number Diff line number Diff line
@@ -79,11 +79,6 @@ static const struct sched_class fair_sched_class; 
 * CFS operations on generic schedulable entities:

 */



static inline struct task_struct *task_of(struct sched_entity *se)

{

	return container_of(se, struct task_struct, se);

}



#ifdef CONFIG_FAIR_GROUP_SCHED



/* cpu runqueue to which this cfs_rq is attached */
@@ -95,6 +90,14 @@ static inline struct rq *rq_of(struct cfs_rq *cfs_rq) 
/* An entity is a task if it doesn't "own" a runqueue */

#define entity_is_task(se)	(!se->my_q)



static inline struct task_struct *task_of(struct sched_entity *se)

{

#ifdef CONFIG_SCHED_DEBUG

	WARN_ON_ONCE(!entity_is_task(se));

#endif

	return container_of(se, struct task_struct, se);

}



/* Walk up scheduling entities hierarchy */

#define for_each_sched_entity(se) \

		for (; se; se = se->parent)
@@ -186,7 +189,12 @@ find_matching_se(struct sched_entity **se, struct sched_entity **pse) 
	}

}



#else	/* CONFIG_FAIR_GROUP_SCHED */

#else	/* !CONFIG_FAIR_GROUP_SCHED */



static inline struct task_struct *task_of(struct sched_entity *se)

{

	return container_of(se, struct task_struct, se);

}



static inline struct rq *rq_of(struct cfs_rq *cfs_rq)

{

kernel/sched_rt.c

+12 −4
Original line number Diff line number Diff line
@@ -3,15 +3,18 @@ 
 * policies)

 */



#ifdef CONFIG_RT_GROUP_SCHED



#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)



static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)

{

#ifdef CONFIG_SCHED_DEBUG

	WARN_ON_ONCE(!rt_entity_is_task(rt_se));

#endif

	return container_of(rt_se, struct task_struct, rt);

}



#ifdef CONFIG_RT_GROUP_SCHED



#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)



static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)

{

	return rt_rq->rq;
@@ -26,6 +29,11 @@ static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) 


#define rt_entity_is_task(rt_se) (1)



static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)

{

	return container_of(rt_se, struct task_struct, rt);

}



static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)

{

	return container_of(rt_rq, struct rq, rt);

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