Index: lib/tsan/rtl/tsan_rtl.cc
===================================================================
--- lib/tsan/rtl/tsan_rtl.cc
+++ lib/tsan/rtl/tsan_rtl.cc
@@ -172,20 +172,20 @@
     }
   }
 
-  u64 last_flush = NanoTime();
+  u64 last_flush = MonotonicNanoTime();
   uptr last_rss = 0;
   for (int i = 0;
       atomic_load(&ctx->stop_background_thread, memory_order_relaxed) == 0;
       i++) {
     SleepForMillis(100);
-    u64 now = NanoTime();
+    u64 now = MonotonicNanoTime();
 
     // Flush memory if requested.
     if (flags()->flush_memory_ms > 0) {
       if (last_flush + flags()->flush_memory_ms * kMs2Ns < now) {
         VPrintf(1, "ThreadSanitizer: periodic memory flush\n");
         FlushShadowMemory();
-        last_flush = NanoTime();
+        last_flush = MonotonicNanoTime();
       }
     }
     // GetRSS can be expensive on huge programs, so don't do it every 100ms.
Index: lib/tsan/rtl/tsan_rtl_report.cc
===================================================================
--- lib/tsan/rtl/tsan_rtl_report.cc
+++ lib/tsan/rtl/tsan_rtl_report.cc
@@ -503,7 +503,7 @@
 bool OutputReport(ThreadState *thr, const ScopedReport &srep) {
   if (!flags()->report_bugs || thr->suppress_reports)
     return false;
-  atomic_store_relaxed(&ctx->last_symbolize_time_ns, NanoTime());
+  atomic_store_relaxed(&ctx->last_symbolize_time_ns, MonotonicNanoTime());
   const ReportDesc *rep = srep.GetReport();
   CHECK_EQ(thr->current_report, nullptr);
   thr->current_report = rep;