Hi Juergen,
> -----Original Message-----
> From: Juergen Gross <jgr...@suse.com>
> Subject: [PATCH-for-4.17] xen/sched: fix race in RTDS scheduler
>
> When a domain gets paused the unit runnable state can change to "not
> runnable" without the scheduling lock being involved. This means that
> a specific scheduler isn't involved in this change of runnable state.
>
> In the RTDS scheduler this can result in an inconsistency in case a
> unit is losing its "runnable" capability while the RTDS scheduler's
> scheduling function is active. RTDS will remove the unit from the run
> queue, but doesn't do so for the replenish queue, leading to hitting
> an ASSERT() in replq_insert() later when the domain is unpaused again.
>
> Fix that by removing the unit from the replenish queue as well in this
> case.
>
> Fixes: 7c7b407e7772 ("xen/sched: introduce unit_runnable_state()")
> Signed-off-by: Juergen Gross <jgr...@suse.com>
Thanks for the quick fix.
Release-acked-by: Henry Wang <henry.w...@arm.com>
Kind regards,
Henry
> ---
> xen/common/sched/rt.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/xen/common/sched/rt.c b/xen/common/sched/rt.c
> index d6de25531b..960a8033e2 100644
> --- a/xen/common/sched/rt.c
> +++ b/xen/common/sched/rt.c
> @@ -1087,6 +1087,7 @@ rt_schedule(const struct scheduler *ops, struct
> sched_unit *currunit,
> else if ( !unit_runnable_state(snext->unit) )
> {
> q_remove(snext);
> + replq_remove(ops, snext);
> snext = rt_unit(sched_idle_unit(sched_cpu));
> }
>
> --
> 2.35.3
