[XdsClient] fix edge case found by fuzzer

markdroth · Feb 13, 2025 · 6f52966 · 6f52966
1 parent 822f9b1
commit 6f52966
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diff --git a/src/core/xds/xds_client/xds_client.cc b/src/core/xds/xds_client/xds_client.cc
@@ -476,6 +476,12 @@ void XdsClient::XdsChannel::UnsubscribeLocked(const XdsResourceType* type,
       if (!call->HasSubscribedResources()) {
         ads_call_.reset();
       }
+    } else {
+      // If there is currently no ADS call because we're in retry backoff,
+      // then we immediately trigger deletion of unsubscribed cache entries.
+      // This may orphan the XdsChannel, which would stop the retry
+      // timer, since we would no longer need to restart the ADS call.
+      xds_client_->MaybeRemoveUnsubscribedCacheEntriesForTypeLocked(this, type);
     }
   }
 }

diff --git a/test/core/xds/xds_client_fuzzer.cc b/test/core/xds/xds_client_fuzzer.cc
@@ -606,4 +606,56 @@ TEST(XdsClientFuzzer, IgnoresConnectionFailuresWithOkStatus) {
   )pb"));
 }
 
+TEST(XdsClientFuzzer, UnsubscribeWhileAdsCallInBackoff) {
+  Fuzz(ParseTestProto(R"pb(
+    bootstrap: "{\"xds_servers\": [{\"server_uri\":\"xds.example.com:443\", \"channel_creds\":[{\"type\": \"fake\"}]}]}"
+    actions {
+      start_watch {
+        resource_type { listener {} }
+        resource_name: "server.example.com"
+      }
+    }
+    actions { send_status_to_client { stream_id { ads {} } } }
+    actions {
+      stop_watch {
+        resource_type { listener {} }
+        resource_name: "server.example.com"
+      }
+    }
+    actions {
+      send_message_to_client {
+        stream_id { ads {} }
+        response {
+          version_info: "1"
+          nonce: "A"
+          type_url: "type.googleapis.com/envoy.config.listener.v3.Listener"
+          resources {
+            [type.googleapis.com/envoy.config.listener.v3.Listener] {
+              name: "server.example.com"
+              api_listener {
+                api_listener {
+                  [type.googleapis.com/envoy.extensions.filters.network
+                       .http_connection_manager.v3.HttpConnectionManager] {
+                    http_filters {
+                      name: "router"
+                      typed_config {
+                        [type.googleapis.com/
+                         envoy.extensions.filters.http.router.v3.Router] {}
+                      }
+                    }
+                    rds {
+                      route_config_name: "route_config"
+                      config_source { self {} }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  )pb"));
+}
+
 }  // namespace grpc_core