Since the execlists_active() is no longer protected by the
engine->active.lock, we need to protect the request pointer with RCU to
prevent it being freed as we evaluate whether or not we need to preempt.
Fixes: df403069029d ("drm/i915/execlists: Lift process_csb() out of the irq-off
spinlock")
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuopp...@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursu...@intel.com>
---
drivers/gpu/drm/i915/i915_scheduler.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c
b/drivers/gpu/drm/i915/i915_scheduler.c
index d2edb527dcb8..010d67f48ad9 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -202,21 +202,26 @@ static void kick_submission(struct intel_engine_cs
*engine,
if (prio <= engine->execlists.queue_priority_hint)
return;
+ rcu_read_lock();
+
/* Nothing currently active? We're overdue for a submission! */
inflight = execlists_active(&engine->execlists);
if (!inflight)
- return;
+ goto unlock;
/*
* If we are already the currently executing context, don't
* bother evaluating if we should preempt ourselves.
*/
if (inflight->hw_context == rq->hw_context)
- return;
+ goto unlock;
engine->execlists.queue_priority_hint = prio;
if (need_preempt(prio, rq_prio(inflight)))
tasklet_hi_schedule(&engine->execlists.tasklet);
+
+unlock:
+ rcu_read_unlock();
}
static void __i915_schedule(struct i915_sched_node *node,
--
2.24.0.rc2
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