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authorThomas Gleixner <tglx@linutronix.de>2009-12-09 09:32:03 +0100
committerIngo Molnar <mingo@elte.hu>2009-12-09 10:01:07 +0100
commitdba091b9e3522b9d32fc9975e48d3b69633b45f0 (patch)
tree91549e3921971b6d0074fd34c29223b593381c8a /kernel/sched.c
parent3160568371da441b7f2fb57f2f1225404207e8f2 (diff)
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sched: Protect sched_rr_get_param() access to task->sched_class
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>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index c4635f7..68db5a2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6887,6 +6887,8 @@ 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;
@@ -6903,7 +6905,9 @@ 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);
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