From 8f48894fcc89ddec62e1762f73a0825793e59e91 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 24 Jul 2009 12:25:30 +0200 Subject: [PATCH] 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: Ingo Molnar Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 20 ++++++++++++++------ kernel/sched_rt.c | 18 +++++++++++++----- 2 files changed, 27 insertions(+), 11 deletions(-) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 49347298487..342000b31ad 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -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) { diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 13f728ef5b3..f365e66b3d4 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -3,15 +3,18 @@ * policies) */ -static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) -{ - 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 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); +} + 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);