Thanks for reporting the problem. It was caused because of the fact that
current task isn't kept in its runqueue in case of sched_fair class
tasks.
With the patch below, I could run ns_exec w/o any crash. Can you pls
verify it works for you as well?
Ingo,
Once Suka verifies that the patch fixes his crash, I would request you
to include the same in your tree and route it to Linus.
--
current task is not present in its runqueue in case of sched_fair class
tasks. Take care of this fact in rt_mutex_setprio(),
sched_setscheduler() and sched_move_task() routines.
Signed-off-by : Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
---
kernel/sched.c | 45 +++++++++++++++++++++++++--------------------
1 files changed, 25 insertions(+), 20 deletions(-)
Index: current/kernel/sched.c
===================================================================
--- current.orig/kernel/sched.c
+++ current/kernel/sched.c
@@ -3986,11 +3986,13 @@ void rt_mutex_setprio(struct task_struct
oldprio = p->prio;
on_rq = p->se.on_rq;
running = task_running(rq, p);
- if (on_rq) {
+ if (on_rq)
dequeue_task(rq, p, 0);
- if (running)
- p->sched_class->put_prev_task(rq, p);
- }
+ /* current task is not kept in its runqueue in case of sched_fair class.
+ * Hence we need the 'on_rq?' and 'running?' tests to be separate.
+ */
+ if (running)
+ p->sched_class->put_prev_task(rq, p);
if (rt_prio(prio))
p->sched_class = &rt_sched_class;
@@ -3999,9 +4001,9 @@ void rt_mutex_setprio(struct task_struct
p->prio = prio;
+ if (running)
+ p->sched_class->set_curr_task(rq);
if (on_rq) {
- if (running)
- p->sched_class->set_curr_task(rq);
enqueue_task(rq, p, 0);
inc_load(rq, p);
/*
@@ -4298,18 +4300,20 @@ recheck:
update_rq_clock(rq);
on_rq = p->se.on_rq;
running = task_running(rq, p);
- if (on_rq) {
+ if (on_rq)
deactivate_task(rq, p, 0);
- if (running)
- p->sched_class->put_prev_task(rq, p);
- }
+ /* current task is not kept in its runqueue in case of sched_fair class.
+ * Hence we need the 'on_rq?' and 'running?' tests to be separate.
+ */
+ if (running)
+ p->sched_class->put_prev_task(rq, p);
oldprio = p->prio;
__setscheduler(rq, p, policy, param->sched_priority);
+ if (running)
+ p->sched_class->set_curr_task(rq);
if (on_rq) {
- if (running)
- p->sched_class->set_curr_task(rq);
activate_task(rq, p, 0);
/*
* Reschedule if we are currently running on this runqueue and
@@ -7036,19 +7040,20 @@ void sched_move_task(struct task_struct
running = task_running(rq, tsk);
on_rq = tsk->se.on_rq;
- if (on_rq) {
+ if (on_rq)
dequeue_task(rq, tsk, 0);
- if (unlikely(running))
- tsk->sched_class->put_prev_task(rq, tsk);
- }
+ /* current task is not kept in its runqueue in case of sched_fair class.
+ * Hence we need the 'on_rq?' and 'running?' tests to be separate.
+ */
+ if (unlikely(running))
+ tsk->sched_class->put_prev_task(rq, tsk);
set_task_cfs_rq(tsk);
- if (on_rq) {
- if (unlikely(running))
- tsk->sched_class->set_curr_task(rq);
+ if (unlikely(running))
+ tsk->sched_class->set_curr_task(rq);
+ if (on_rq)
enqueue_task(rq, tsk, 0);
- }
done:
task_rq_unlock(rq, &flags);
--
Regards,
vatsa
-
