diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2009-12-09 09:32:03 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-09-20 13:17:57 -0700 |
| commit | 34d1f22e7617964c395c9e6022d8cf718558fcce (patch) | |
| tree | 8726e8ec955b39072e8567b6b598438656fc0d83 | |
| parent | 7272e504cb1f35861e59fade3628f047f897afff (diff) | |
sched: Protect sched_rr_get_param() access to task->sched_class
commit dba091b9e3522b9d32fc9975e48d3b69633b45f0 upstream
sched_rr_get_param calls
task->sched_class->get_rr_interval(task) without protection
against a concurrent sched_setscheduler() call which modifies
task->sched_class.
Serialize the access with task_rq_lock(task) and hand the rq
pointer into get_rr_interval() as it's needed at least in the
sched_fair implementation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <alpine.LFD.2.00.0912090930120.3089@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | include/linux/sched.h | 3 | ||||
| -rw-r--r-- | kernel/sched.c | 6 | ||||
| -rw-r--r-- | kernel/sched_fair.c | 6 | ||||
| -rw-r--r-- | kernel/sched_idletask.c | 2 | ||||
| -rw-r--r-- | kernel/sched_rt.c | 2 |
5 files changed, 10 insertions, 9 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index cc24bebf8019..6d42a524497c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1114,7 +1114,8 @@ struct sched_class { void (*prio_changed) (struct rq *this_rq, struct task_struct *task, int oldprio, int running); - unsigned int (*get_rr_interval) (struct task_struct *task); + unsigned int (*get_rr_interval) (struct rq *rq, + struct task_struct *task); #ifdef CONFIG_FAIR_GROUP_SCHED void (*moved_group) (struct task_struct *p); diff --git a/kernel/sched.c b/kernel/sched.c index eaf30be616e5..8554f124a3e9 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6946,6 +6946,8 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, { struct task_struct *p; unsigned int time_slice; + unsigned long flags; + struct rq *rq; int retval; struct timespec t; @@ -6962,7 +6964,9 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, if (retval) goto out_unlock; - time_slice = p->sched_class->get_rr_interval(p); + rq = task_rq_lock(p, &flags); + time_slice = p->sched_class->get_rr_interval(rq, p); + task_rq_unlock(rq, &flags); read_unlock(&tasklist_lock); jiffies_to_timespec(time_slice, &t); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index d80812d39d62..803a9d2afcfa 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2003,21 +2003,17 @@ static void moved_group_fair(struct task_struct *p) } #endif -unsigned int get_rr_interval_fair(struct task_struct *task) +unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) { struct sched_entity *se = &task->se; - unsigned long flags; - struct rq *rq; unsigned int rr_interval = 0; /* * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise * idle runqueue: */ - rq = task_rq_lock(task, &flags); if (rq->cfs.load.weight) rr_interval = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); - task_rq_unlock(rq, &flags); return rr_interval; } diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c index b133a28fcde3..33d5384a73a8 100644 --- a/kernel/sched_idletask.c +++ b/kernel/sched_idletask.c @@ -97,7 +97,7 @@ static void prio_changed_idle(struct rq *rq, struct task_struct *p, check_preempt_curr(rq, p, 0); } -unsigned int get_rr_interval_idle(struct task_struct *task) +unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task) { return 0; } diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index a4d790cddb19..a9320d46046b 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1734,7 +1734,7 @@ static void set_curr_task_rt(struct rq *rq) dequeue_pushable_task(rq, p); } -unsigned int get_rr_interval_rt(struct task_struct *task) +unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task) { /* * Time slice is 0 for SCHED_FIFO tasks |