On 08/03/2017 18:46, Steven Rostedt wrote:
> On Wed, 8 Mar 2017 12:40:12 -0500
> Steven Rostedt <rost...@goodmis.org> wrote:
>
>> I wonder if we should just have a special flag sent by that sysrq
>> trigger. Since it is causing all tasks to go "nice" there's no need to
>> do the pi chain walk in __sched_setscheduler().
>
> Hah, there already is a flag!
>
> Laurent, can you test this patch:
Tested on ppc64, no more panic \o/
FWIW,
Tested-by: Laurent Dufour <lduf...@linux.vnet.ibm.com>
Thanks,
Laurent.
>
> -- Steve
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 3b31fc0..7292fa9 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4129,8 +4129,8 @@ static int __sched_setscheduler(struct task_struct *p,
> int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE;
> struct rq *rq;
>
> - /* May grab non-irq protected spin_locks: */
> - BUG_ON(in_interrupt());
> + /* The pi code expects interrupts enabled */
> + BUG_ON(pi && in_interrupt());
> recheck:
> /* Double check policy once rq lock held: */
> if (policy < 0) {
>
