• Hiroshi Shimamoto's avatar
    sched: fix invalid sched_class use · 9c95e731
    Hiroshi Shimamoto authored
    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: default avatarHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
    9c95e731
sched.c 166 KB