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| author | Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> | 2007-09-20 01:34:46 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-09-20 01:34:46 +0400 |
| commit | 9c95e7319ba98585ebb6d304eca2d56f401ed70c (patch) | |
| tree | b650a409da9c1e1feb289cfb16ce2fa05c602216 /kernel | |
| parent | 1799e35d5baab6e06168b46cc78b968e728ea3d1 (diff) | |
| download | linux-9c95e7319ba98585ebb6d304eca2d56f401ed70c.tar.xz | |
sched: fix invalid sched_class use
When using rt_mutex, a NULL pointer dereference is occurred at
enqueue_task_rt. Here is a scenario;
1) there are two threads, the thread A is fair_sched_class and
thread B is rt_sched_class.
2) Thread A is boosted up to rt_sched_class, because the thread A
has a rt_mutex lock and the thread B is waiting the lock.
3) At this time, when thread A create a new thread C, the thread
C has a rt_sched_class.
4) When doing wake_up_new_task() for the thread C, the priority
of the thread C is out of the RT priority range, because the
normal priority of thread A is not the RT priority. It makes
data corruption by overflowing the rt_prio_array.
The new thread C should be fair_sched_class.
The new thread should be valid scheduler class before queuing.
This patch fixes to set the suitable scheduler class.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 63e0971c8fbb..6107a0cd6325 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1682,6 +1682,11 @@ void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) p->prio = effective_prio(p); + if (rt_prio(p->prio)) + p->sched_class = &rt_sched_class; + else + p->sched_class = &fair_sched_class; + if (!p->sched_class->task_new || !sysctl_sched_child_runs_first || (clone_flags & CLONE_VM) || task_cpu(p) != this_cpu || !current->se.on_rq) { |