Add logging when starting a trace iteration while one is already in progress

Should help identify if we are trying to start tracing iterations concurrently and if that might be leading to race conditions that we are not handling.

Change-Id: If9f6ac5e9dd5b5c0f8e9bb6eb04b10fec374d3e1
Flag: EXEMPT logging only
Bug: 393585228

1 files changed, 3 insertions, 0 deletions

diff --git a/core/jni/android_tracing_PerfettoDataSource.cpp b/core/jni/android_tracing_PerfettoDataSource.cpp
index ea896e1678a7..56ee3dcf7ca5 100644
--- a/core/jni/android_tracing_PerfettoDataSource.cpp
+++ b/core/jni/android_tracing_PerfettoDataSource.cpp
@@ -96,6 +96,9 @@ jobject PerfettoDataSource::newInstance(JNIEnv* env, void* ds_config, size_t ds_
 
 bool PerfettoDataSource::TraceIterateBegin() {
     if (gInIteration) {
+        ALOG(LOG_ERROR, LOG_TAG,
+              "Tried calling TraceIterateBegin with an already active iterator for datasource %s.",
+              dataSourceName.c_str());
         return false;
     }