From: Juergen Gross Date: Mon, 31 Oct 2022 12:22:54 +0000 (+0100) Subject: xen/sched: fix race in RTDS scheduler X-Git-Tag: RELEASE-4.16.3~84 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=481465f35da1bcec0b2a4dfd6fc51d86cac28547;p=xen.git 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 Acked-by: Dario Faggioli master commit: 73c62927f64ecb48f27d06176befdf76b879f340 master date: 2022-10-21 12:32:23 +0200 --- diff --git a/xen/common/sched/rt.c b/xen/common/sched/rt.c index c24cd2ac32..ec2ca1bebc 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)); }