From: Steven Rostedt <rostedt@xxxxxxxxxxx> The wait_task_interactive() will have a task sleep waiting for another task to have a certain state. But it ignores the rt_spin_locks state and can return with an incorrect result if the task it is waiting for is blocked on a rt_spin_lock() and is waking up. The rt_spin_locks save the tasks state in the saved_state field and the wait_task_interactive() must also test that state. Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Carsten Emde <C.Emde@xxxxxxxxx> Cc: John Kacur <jkacur@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Clark Williams <clark.williams@xxxxxxxxx> Cc: stable-rt@xxxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/20120301190345.979435764@xxxxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- kernel/sched.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index e5ef7a8..df30481 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2284,7 +2284,8 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state) * is actually now running somewhere else! */ while (task_running(rq, p)) { - if (match_state && unlikely(p->state != match_state)) + if (match_state && unlikely(p->state != match_state) + && unlikely(p->saved_state != match_state)) return 0; cpu_relax(); } @@ -2299,7 +2300,8 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state) running = task_running(rq, p); on_rq = p->on_rq; ncsw = 0; - if (!match_state || p->state == match_state) + if (!match_state || p->state == match_state + || p->saved_state == match_state) ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ task_rq_unlock(rq, p, &flags); -- 1.7.8.3 -- To unsubscribe from this list: send the line "unsubscribe stable-rt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
