4 files changed, 36 insertions, 6 deletions
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index d576f85dd2..3ee5e976f8 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -168,7 +168,7 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
   grpc_chttp2_stream_map_destroy(&t->stream_map);
   grpc_connectivity_state_destroy(exec_ctx, &t->channel_callback.state_tracker);
 
-  grpc_combiner_unref(exec_ctx, t->combiner);
+  GRPC_COMBINER_UNREF(exec_ctx, t->combiner, "chttp2_transport");
 
   cancel_pings(exec_ctx, t, GRPC_ERROR_CREATE("Transport destroyed"));
 
diff --git a/src/core/lib/iomgr/combiner.c b/src/core/lib/iomgr/combiner.c
index 9c6bd2728f..fa9966c3a6 100644
--- a/src/core/lib/iomgr/combiner.c
+++ b/src/core/lib/iomgr/combiner.c
@@ -163,13 +163,26 @@ static void start_destroy(grpc_exec_ctx *exec_ctx, grpc_combiner *lock) {
   }
 }
 
-void grpc_combiner_unref(grpc_exec_ctx *exec_ctx, grpc_combiner *lock) {
+#ifdef GRPC_COMBINER_REFCOUNT_DEBUG
+#define GRPC_COMBINER_DEBUG_SPAM(op, delta)                               \
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,                             \
+          "combiner[%p] %s %" PRIdPTR " --> %" PRIdPTR " %s", lock, (op), \
+          gpr_atm_no_barrier_load(&lock->refs.count),                     \
+          gpr_atm_no_barrier_load(&lock->refs.count) + (delta), reason);
+#else
+#define GRPC_COMBINER_DEBUG_SPAM(op, delta)
+#endif
+
+void grpc_combiner_unref(grpc_exec_ctx *exec_ctx,
+                         grpc_combiner *lock GRPC_COMBINER_DEBUG_ARGS) {
+  GRPC_COMBINER_DEBUG_SPAM("UNREF", -1);
   if (gpr_unref(&lock->refs)) {
     start_destroy(exec_ctx, lock);
   }
 }
 
-grpc_combiner *grpc_combiner_ref(grpc_combiner *lock) {
+grpc_combiner *grpc_combiner_ref(grpc_combiner *lock GRPC_COMBINER_DEBUG_ARGS) {
+  GRPC_COMBINER_DEBUG_SPAM("  REF", 1);
   gpr_ref(&lock->refs);
   return lock;
 }
diff --git a/src/core/lib/iomgr/combiner.h b/src/core/lib/iomgr/combiner.h
index d257150058..f1fa941d64 100644
--- a/src/core/lib/iomgr/combiner.h
+++ b/src/core/lib/iomgr/combiner.h
@@ -48,9 +48,26 @@
 // Initialize the lock, with an optional workqueue to shift load to when
 // necessary
 grpc_combiner *grpc_combiner_create(grpc_workqueue *optional_workqueue);
+
+//#define GRPC_COMBINER_REFCOUNT_DEBUG
+#ifdef GRPC_COMBINER_REFCOUNT_DEBUG
+#define GRPC_COMBINER_DEBUG_ARGS \
+  , const char *file, int line, const char *reason
+#define GRPC_COMBINER_REF(combiner, reason) \
+  grpc_combiner_ref((combiner), __FILE__, __LINE__, (reason))
+#define GRPC_COMBINER_UNREF(exec_ctx, combiner, reason) \
+  grpc_combiner_unref((exec_ctx), (combiner), __FILE__, __LINE__, (reason))
+#else
+#define GRPC_COMBINER_DEBUG_ARGS
+#define GRPC_COMBINER_REF(combiner) grpc_combiner_ref((combiner))
+#define GRPC_COMBINER_UNREF(exec_ctx, combiner) \
+  grpc_combiner_unref((exec_ctx), (combiner))
+#endif
+
 // Ref/unref the lock, for when we're sharing the lock ownership
-grpc_combiner *grpc_combiner_ref(grpc_combiner *lock);
-void grpc_combiner_unref(grpc_exec_ctx *exec_ctx, grpc_combiner *lock);
+grpc_combiner *grpc_combiner_ref(grpc_combiner *lock GRPC_COMBINER_DEBUG_ARGS);
+void grpc_combiner_unref(grpc_exec_ctx *exec_ctx,
+                         grpc_combiner *lock GRPC_COMBINER_DEBUG_ARGS);
 // Fetch a scheduler to schedule closures against
 grpc_closure_scheduler *grpc_combiner_scheduler(grpc_combiner *lock,
                                                 bool covered_by_poller);
diff --git a/src/core/lib/iomgr/resource_quota.c b/src/core/lib/iomgr/resource_quota.c
index 3c701164ad..511ffdcdf1 100644
--- a/src/core/lib/iomgr/resource_quota.c
+++ b/src/core/lib/iomgr/resource_quota.c
@@ -599,7 +599,7 @@ grpc_resource_quota *grpc_resource_quota_create(const char *name) {
 void grpc_resource_quota_unref_internal(grpc_exec_ctx *exec_ctx,
                                         grpc_resource_quota *resource_quota) {
   if (gpr_unref(&resource_quota->refs)) {
-    grpc_combiner_unref(exec_ctx, resource_quota->combiner);
+    GRPC_COMBINER_UNREF(exec_ctx, resource_quota->combiner, "resource_quota");
     gpr_free(resource_quota->name);
     gpr_free(resource_quota);
   }