Subject: sched/rt: Fix wait_task_interactive() to test rt_spin_lock state From: Steven Rostedt Date: Thu, 01 Mar 2012 13:55:33 -0500 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 Cc: Carsten Emde Cc: John Kacur Cc: Peter Zijlstra Cc: Clark Williams Cc: stable-rt@vger.kernel.org Link: http://lkml.kernel.org/r/20120301190345.979435764@goodmis.org Signed-off-by: Thomas Gleixner --- kernel/sched/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) Index: linux-stable/kernel/sched/core.c =================================================================== --- linux-stable.orig/kernel/sched/core.c +++ linux-stable/kernel/sched/core.c @@ -1172,7 +1172,8 @@ unsigned long wait_task_inactive(struct * 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(); } @@ -1187,7 +1188,8 @@ unsigned long wait_task_inactive(struct 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);