[PATCH 13/15] sched: convert numa_group.refcount from atomic_t to refcount_t

refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Suggested-by: Kees Cook <keescook(a)chromium.org&gt; Reviewed-by: David Windsor <dwindsor(a)gmail.com&gt; Reviewed-by: Hans Liljestrand <ishkamiel(a)gmail.com&gt; Signed-off-by: Elena Reshetova <elena.reshetova(a)intel.com&gt; --- kernel/sched/fair.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c95880e..5f7f997 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1130,7 +1130,7 @@ static void account_numa_dequeue(struct rq *rq, struct task_struct *p) } struct numa_group { - atomic_t refcount; + refcount_t refcount; spinlock_t lock; /* nr_tasks, tasks */ int nr_tasks; @@ -2177,12 +2177,12 @@ static void task_numa_placement(struct task_struct *p) static inline int get_numa_group(struct numa_group *grp) { - return atomic_inc_not_zero(&grp->refcount); + return refcount_inc_not_zero(&grp->refcount); } static inline void put_numa_group(struct numa_group *grp) { - if (atomic_dec_and_test(&grp->refcount)) + if (refcount_dec_and_test(&grp->refcount)) kfree_rcu(grp, rcu); } @@ -2203,7 +2203,7 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags, if (!grp) return; - atomic_set(&grp->refcount, 1); + refcount_set(&grp->refcount, 1); grp->active_nodes = 1; grp->max_faults_cpu = 0; spin_lock_init(&grp->lock); -- 2.7.4