diff --git a/compiler-rt/lib/tsan/rtl/tsan_flags.inc b/compiler-rt/lib/tsan/rtl/tsan_flags.inc
--- a/compiler-rt/lib/tsan/rtl/tsan_flags.inc
+++ b/compiler-rt/lib/tsan/rtl/tsan_flags.inc
@@ -43,6 +43,10 @@
     bool, force_seq_cst_atomics, false,
     "If set, all atomics are effectively sequentially consistent (seq_cst), "
     "regardless of what user actually specified.")
+TSAN_FLAG(
+    bool, force_background_thread, false,
+    "If set, eagerly launch a background thread for memory reclamation "
+    "instead of waiting for a user call to pthread_create.");
 TSAN_FLAG(bool, halt_on_error, false, "Exit after first reported error.")
 TSAN_FLAG(int, atexit_sleep_ms, 1000,
           "Sleep in main thread before exiting for that many ms "
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp b/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
@@ -698,6 +698,15 @@
   OnInitialize();
 }
 
+#if !SANITIZER_GO
+static bool UNUSED __local_tsan_dyninit = [] {
+  if (flags()->force_background_thread) {
+    MaybeSpawnBackgroundThread();
+  }
+  return false;
+}();
+#endif
+
 void MaybeSpawnBackgroundThread() {
   // On MIPS, TSan initialization is run before
   // __pthread_initialize_minimal_internal() is finished, so we can not spawn
diff --git a/compiler-rt/test/tsan/force_background_thread.cpp b/compiler-rt/test/tsan/force_background_thread.cpp
new file mode 100644
--- /dev/null
+++ b/compiler-rt/test/tsan/force_background_thread.cpp
@@ -0,0 +1,25 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && %deflake %env_tsan_opts=force_background_thread=0 %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_tsan -O1 %s -o %t && %deflake %env_tsan_opts=force_background_thread=1 %run %t 2>&1 | FileCheck %s
+#include "test.h"
+#include <pthread.h>
+#include <stddef.h>
+#include <stdio.h>
+
+void *Thread(void *a) {
+  ((int *)a)[0]++;
+  barrier_wait(&barrier);
+  return NULL;
+}
+
+int main() {
+  barrier_init(&barrier, 2);
+  int *p = new int(42);
+  pthread_t t;
+  pthread_create(&t, NULL, Thread, p);
+  barrier_wait(&barrier);
+  p[0]++;
+  pthread_join(t, NULL);
+  delete p;
+}
+
+// CHECK: WARNING: ThreadSanitizer: data race