Done right this time...

src/core/ext/client_config/subchannel.c

@@ -651,7 +651,7 @@ static void subchannel_call_destroy(grpc_exec_ctx *exec_ctx, void *call,
                                     bool success) {
   grpc_subchannel_call *c = call;
   GPR_TIMER_BEGIN("grpc_subchannel_call_unref.destroy", 0);
-  grpc_call_stack_destroy(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c));
+  grpc_call_stack_destroy(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c), NULL);
   GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, c->connection, "subchannel_call");
   gpr_free(c);
   GPR_TIMER_END("grpc_subchannel_call_unref.destroy", 0);

src/core/lib/channel/channel_stack.c

@@ -169,7 +169,6 @@ void grpc_call_stack_init(grpc_exec_ctx *exec_ctx,
   size_t i;
 
   call_stack->count = count;
-  memset(&call_stack->stats, 0, sizeof(grpc_call_stats));
   GRPC_STREAM_REF_INIT(&call_stack->refcount, initial_refs, destroy,
                        destroy_arg, "CALL_STACK");
   call_elems = CALL_ELEMS_FROM_STACK(call_stack);
@@ -214,14 +213,15 @@ void grpc_call_stack_ignore_set_pollset(grpc_exec_ctx *exec_ctx,
                                         grpc_call_element *elem,
                                         grpc_pollset *pollset) {}
 
-void grpc_call_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_call_stack *stack) {
+void grpc_call_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_call_stack *stack,
+                             const grpc_call_stats *call_stats) {
   grpc_call_element *elems = CALL_ELEMS_FROM_STACK(stack);
   size_t count = stack->count;
   size_t i;
 
   /* destroy per-filter data */
   for (i = 0; i < count; i++) {
-    elems[i].filter->destroy_call_elem(exec_ctx, &elems[i], &stack->stats);
+    elems[i].filter->destroy_call_elem(exec_ctx, &elems[i], call_stats);
   }
 }
 

src/core/lib/channel/channel_stack.h

@@ -173,7 +173,6 @@ struct grpc_call_stack {
      about the address of the call stack itself. */
   grpc_stream_refcount refcount;
   size_t count;
-  grpc_call_stats stats;
 };
 
 /* Get a channel element given a channel stack and its index */
@@ -233,7 +232,8 @@ void grpc_call_stack_set_pollset(grpc_exec_ctx *exec_ctx,
 #endif
 
 /* Destroy a call stack */
-void grpc_call_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_call_stack *stack);
+void grpc_call_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_call_stack *stack,
+                             const grpc_call_stats *call_stats);
 
 /* Ignore set pollset - used by filters to implement the set_pollset method
    if they don't care about pollsets at all. Does nothing. */

src/core/lib/surface/call.c

@@ -175,7 +175,7 @@ struct grpc_call {
   received_status status[STATUS_SOURCE_COUNT];
 
   /* Call stats: only valid after trailing metadata received */
-  grpc_transport_stream_stats stats;
+  grpc_call_stats stats;
 
   /* Compression algorithm for the call */
   grpc_compression_algorithm compression_algorithm;
@@ -375,7 +375,7 @@ static void destroy_call(grpc_exec_ctx *exec_ctx, void *call, bool success) {
   if (c->receiving_stream != NULL) {
     grpc_byte_stream_destroy(exec_ctx, c->receiving_stream);
   }
-  grpc_call_stack_destroy(exec_ctx, CALL_STACK_FROM_CALL(c));
+  grpc_call_stack_destroy(exec_ctx, CALL_STACK_FROM_CALL(c), &c->stats);
   GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, c->channel, "call");
   gpr_mu_destroy(&c->mu);
   for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
@@ -1392,7 +1392,7 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         bctl->recv_final_op = 1;
         stream_op.recv_trailing_metadata =
             &call->metadata_batch[1 /* is_receiving */][1 /* is_trailing */];
-        stream_op.collect_stats = &call->stats;
+        stream_op.collect_stats = &call->stats.transport_stream_stats;
         break;
       case GRPC_OP_RECV_CLOSE_ON_SERVER:
         /* Flag validation: currently allow no flags */
@@ -1414,7 +1414,7 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         bctl->recv_final_op = 1;
         stream_op.recv_trailing_metadata =
             &call->metadata_batch[1 /* is_receiving */][1 /* is_trailing */];
-        stream_op.collect_stats = &call->stats;
+        stream_op.collect_stats = &call->stats.transport_stream_stats;
         break;
     }
   }

test/core/channel/channel_stack_test.c

@@ -87,7 +87,7 @@ static void free_channel(grpc_exec_ctx *exec_ctx, void *arg, bool success) {
 }
 
 static void free_call(grpc_exec_ctx *exec_ctx, void *arg, bool success) {
-  grpc_call_stack_destroy(exec_ctx, arg);
+  grpc_call_stack_destroy(exec_ctx, arg, NULL);
   gpr_free(arg);
 }