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| author | Thomas Gleixner <tglx@linutronix.de> | 2009-12-09 09:32:03 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-09 10:01:07 +0100 |
| commit | dba091b9e3522b9d32fc9975e48d3b69633b45f0 (patch) | |
| tree | 91549e3921971b6d0074fd34c29223b593381c8a /kernel/sched.c | |
| parent | 3160568371da441b7f2fb57f2f1225404207e8f2 (diff) | |
| download | lwn-dba091b9e3522b9d32fc9975e48d3b69633b45f0.tar.gz lwn-dba091b9e3522b9d32fc9975e48d3b69633b45f0.zip | |
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.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index c4635f74540c..68db5a2e6545 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); |