Explictly Flush exec_ctx after resetting call_combiner_set_notify_on_cancel to avoid the need to take refs on the stack for cancellation closures on exec_ctx

1 files changed, 4 insertions, 1 deletions

diff --git a/src/core/lib/iomgr/call_combiner.h b/src/core/lib/iomgr/call_combiner.h
index 641fa18082..6f7ddd4043 100644
--- a/src/core/lib/iomgr/call_combiner.h
+++ b/src/core/lib/iomgr/call_combiner.h
@@ -102,7 +102,10 @@ void grpc_call_combiner_stop(grpc_call_combiner* call_combiner,
 /// If \a closure is NULL, then no closure will be invoked on
 /// cancellation; this effectively unregisters the previously set closure.
 /// However, most filters will not need to explicitly unregister their
-/// callbacks, as this is done automatically when the call is destroyed.
+/// callbacks, as this is done automatically when the call is destroyed. Filters
+/// that schedule the cancellation closure on ExecCtx do not need to take a ref
+/// on the call stack to guarantee closure liveness. This is done by explicitly
+/// flushing ExecCtx after the unregistration during call destruction.
 void grpc_call_combiner_set_notify_on_cancel(grpc_call_combiner* call_combiner,
                                              grpc_closure* closure);