diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 15d56cd3937e3335375434acca28760d4b122c2d..b9b3f78f13240a44dfe472783a4f47982e75bc86 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1448,6 +1448,7 @@ assert_pending_valid(const struct intel_engine_execlists *execlists,
 {
 	struct i915_request * const *port, *rq;
 	struct intel_context *ce = NULL;
+	bool sentinel = false;
 
 	trace_ports(execlists, msg, execlists->pending);
 
@@ -1481,6 +1482,26 @@ assert_pending_valid(const struct intel_engine_execlists *execlists,
 		}
 		ce = rq->context;
 
+		/*
+		 * Sentinels are supposed to be lonely so they flush the
+		 * current exection off the HW. Check that they are the
+		 * only request in the pending submission.
+		 */
+		if (sentinel) {
+			GEM_TRACE_ERR("context:%llx after sentinel in pending[%zd]\n",
+				      ce->timeline->fence_context,
+				      port - execlists->pending);
+			return false;
+		}
+
+		sentinel = i915_request_has_sentinel(rq);
+		if (sentinel && port != execlists->pending) {
+			GEM_TRACE_ERR("sentinel context:%llx not in prime position[%zd]\n",
+				      ce->timeline->fence_context,
+				      port - execlists->pending);
+			return false;
+		}
+
 		/* Hold tightly onto the lock to prevent concurrent retires! */
 		if (!spin_trylock_irqsave(&rq->lock, flags))
 			continue;